Quasi-Chalcogen Characteristics of Al12Be: A New Member of the

Subscriber access provided by GAZI UNIV

Article 12

Quasi-chalcogen Characteristics of Al Be: A New Member of Three-dimensional Periodic Table Wei-Ming Sun, Di Wu, Xiang-Hui Li, Ying Li, Jing-Hua Chen, Chunyan Li, Jia-Yuan Liu, and Zhi-Ru Li J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.5b11917 • Publication Date (Web): 08 Jan 2016 Downloaded from http://pubs.acs.org on January 12, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

The Journal of Physical Chemistry C is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

Quasi-chalcogen Characteristics of Al12Be: a New Member of Threedimensional Periodic Table *

Wei-Ming Suna,b, Di Wua, Xiang-Hui Lic, Ying Lia , Jing-Hua Chenb, Chun-Yan Lib, Jia-Yuan Liua, Zhi-Ru Lia a

Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China

b c

Faculty of Pharmacy, Fujian Medical University, Fuzhou 350108, People’s Republic of China Medical Technology and Engineering College, Fujian Medical University, Fuzhou 350004, Fujian, China

ABSTRACT: The creative concept of superatom brings a new dimension to the conventional periodic table, which has been gradually enriched by both theoretical and experimental researches. In this article, we propose a new member, namely Al12Be, to the superatom family. The amazing similarity between the Al12Be cluster and the chalcogen elements makes the former an excellent superatom counterpart of the latter. In addition, Al12Be exhibits more exothermic first electron affinity (EA) and less endothermic second EA values due to its size advantage over the chalcogen atoms, showing the superatom superiority in this respect. The stable compounds formed between Al 12Be and other atoms, such as carbon, beryllium, calcium, and lithium, provide further evidence to support the quasi-chalcogen identity of Al12Be.

1. INTRODUCTION

model, the valence electrons of the individual atoms move

A breakthrough has been made in the field of cluster sci-

in a spherical positive potential formed by the nuclei and

ence when it is realized that some stable clusters with

innermost electrons, resulting in a shell structure where the

unique electronic structure can mimic the chemical behav-

valence electrons are arranged in 1S2, 1P6, 1D10, 2S2, 1F14,

ior of individual atoms. Khanna and Jena named such clus-

2P6.... subshells. Hence, clusters containing 2, 8, 18, 20, 34,

ters as “superatoms”1,2 and considered them as a three-

40... electrons correspond to closed-shell states. Generally,

dimensional (3D) expansion of the conventional periodic

such species are similar to the noble gas elements of VIIIA

3,4

table . The study of superatoms may also open up a new

group and show high stability and chemical inertness. It is

era of materials science where superatoms, instead of atoms,

also known that the atom-like properties of some

serve as the building blocks of cluster-assembled com-

superatoms usually depend on their electronic and geomet-

5–12

pounds and materials

with tailored properties. Therefore,

exploring and characterizing various superatoms is current-

ric structure being near or adjacent to a closed electronic or geometric shell8. In past decades, the attempts to identify superatom

ly a topic of compelling interest. It is well-known that the properties of clusters vary

motifs have yielded exciting results. Superalkalis and

with size and composition. In principle, as there are endless

superhalogens are two kinds of superatoms with specific

ways to assemble atoms into clusters, it should be possible

features resembling the alkali metal and halogen atoms,

to find the corresponding superatom (maybe more than one)

respectively. Since they were initially proposed by Gutsev

for each atom or group of the traditional periodic table of

and Boldyrev15,16 in the early 1980s, there has been increas-

elements and ultimately achieve an entire 3D periodic table.

ing interest and activity in both experimental17−19 and theo-

During the effort to identify new superatoms, the spherical

retical20−25 studies of these two classes of superatoms. For

jellium model (SJM)13,14 plays an important part. In this

example, the Al13 cluster with 39 valence electrons is one

ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 12

electron short of a closed shell state and hence possesses a

promising candidate for quasi-chalcogen superatoms. By

26

exploring the electronic properties and chemical behavior

demonstrated that the Al14 cluster

of Al12Be, we aim at answering the following questions:

tended to lose two valence electrons to achieve a full shell

How much similarity is there between Al12Be and

and thereby could be classified as superalkaline earth atom.

chalcogen elements? Does the Al12Be cluster prefer to re-

very high electron affinity, just as a halogen atom does. Also, Bergeron et al.

27

28

One year later, Reveles et al. provided evidence of an

ceive two electrons and exist in the form of dianion in its

additional class of superatoms with valence states of +2 and

compounds? Does it form typical CaO-like compounds

+4, which exhibit qualities reminiscent to the C or Si ele-

with (super)alkaline earth atoms? What is amazing is that

29

ments (IVA group). Very recently, Reveles et al. reported

all the analyses in the current study demonstrate the great

that Al12Cu could be considered not only a superatom mim-

resemblance between Al12Be and chalcogens. Consequent-

ic of a phosphorus atom but a stable building block of ionic

ly, the oxygen family also possesses its representative

salts. Consequently, except for boron (IIIA) and oxygen

superatom in the “3D periodic table” now.

(VIA) groups, every main group in the period table already has its representative superatom counterpart up to now. It is rather remarkable that the studies of superatoms have also been extended to simulate the behavior of transition metals and B-subgroup elements. For example, magnetic superatoms firstly introduced by Kumar and Kawazoe30 are a novel subset of superatoms bearing similarity to magnetic transition metal atoms. In 2009, Khanna and 31

coworkers

proposed a strategy for designing magnetic

superatoms by taking VNa8, VCs8, and MnAu24(SH)18 as illustrative examples. Afterwards, they have designed a large number of new magnetic superatoms, such as ScK12,32 ScCs12,32 TiNa9,33 FeMg8,34 FeCa8,35 and MnCa9,36 etc.. In 2013, the existence of VNa8 was confirmed by negative ion photoelectron experiments,37 indicating the feasibility of synthesizing more designer magnetic superatoms. In addition, it has been reported that tungsten carbide (WC) can display platinum-like behavior in surface catalysis while TiO– and ZrO– reveal remarkable similarity to Ni– and Pd–, respectively, which exhibits the potential of using superatoms to replace the expensive metal catalysts. 3 The above findings further reinforce the idea that it is promising to find various superatoms mimicking virtually all kinds of elements to expand the proposed 3D periodic table. In this work, we have focused on the beryllium-doped aluminum cluster Al12Be that has a compact geometrical structure with 38 valence electrons. Being short of two electrons to achieve a closed shell configuration makes it a

2. COMPUTATIONAL DETAILS The potential energy surface of Al12Be has been explored by employing two methods. For the first one, a large amount of initial geometries were constructed artificially by placing a beryllium atom on each possible site of the Al12 cluster,38–40 or substituting a Be atom for one Al atom of Al1338–40. For the other one, the stochastic search procedure23,41 was used, in which all the atoms were placed at a common initial point in geometrical space and then tossed in random directions within a spherical shell with the radius of 6.0 Å. A mass of starting geometries were obtained and then optimized automatically at the B3LYP/LANL2DZ level. During this procedure, the spin multiplicities of 1 (singlet) and 3 (triplet) were considered for each initial geometrical structure. Then, all the possible structures obtained by the above two approaches were optimized at the B3LYP/aug-cc-pVDZ level with frequency calculations to check whether the optimized structures were transition states or true minima on the potential energy surface. At last, the first nine lower-energy isomers of Al12Be were presented and discussed in this work. The optimized structures of their corresponding Al12Be2– dianions were obtained at the same B3LYP/aug-cc-pVDZ level. Based on the lowest-energy structure of Al12Be, the initial structures of (Al12Be)Lin (n = 1–5) were obtained by attaching Li atoms to each possible site of the Al12Be polyhedron and then optimized at the B3LYP/aug-cc-pVDZ level. The equilibrium structures of (Al12Be)Ca and Al12BeM (M = Li,


Page 3 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Be, B, C, N, O, and F) were also gained by the same method. The equilibrium geometries of (Al12Be)FLi3 and (Al12Be)2 were gained by considering different bonding orientations of two subunits at the B3LYP/aug-cc-pVDZ level. Natural

(NBO)42

bond orbital

calculations

of

Table 1. Relative Energies (Erel, in kcal/mol), Symmetry Point Groups, the Number of Be-Al Bonds (N), the Average Be-Al Bond Lengths (RBe-Al, in Å), the Lowest Vibrational Frequencies (v1, in cm−1), Binding Energies Per Atom (Eb, in eV) and HOMO-LUMO Gaps (in eV) of the Al12Be and Al12Be2– Species. Species

Isomer

Al12Be

Erela

Symmetry

N

RBe-Al

v1

Eb

Gap

A

0

D3d

12

2.654

28

2.17

1.56

(Al12Be)FLi3,

B

0.56

Cs

6

2.427

11

2.17

2.25

(Al12Be)C, and (Al12Be)2 were performed at the same level

C

2.91

Cs

12

2.698

21

2.16

1.80

D

5.35

Ci

12

2.638

48

2.15

1.14

E

6.44

Cs

12

2.715

21

2.15

1.88

superatom

compounds

(Al12Be)Ca,

of theory as used in structure optimizations. For the CaO/CaS molecule, the geometrical optimization and NBO

F

8.28

C2v

12

2.654

42

2.14

1.33

G

9.33

Cs

6

2.458

51

2.14

1.99

in conjunction with the 6-311+G(d) basis set for Ca and

H

13.31

Cs

5

2.417

32

2.13

1.85

aug-cc-pVDZ basis set for O and S. All the single point

I

17.67

Cs

5

2.468

32

2.11

2.07

a

0

Ih

12

2.622

97

2.46

2.29

b

19.85

C3h

12

2.681

36

2.39

2.01

c

32.28

C5

6

2.495

28

2.35

2.11

calculation were performed by using the B3LYP functional

energy calculations in the present work employed the

Al12Be

CCSD(T) method. All calculations were performed by using the

2–

d

37.73

D5d

12

2.652

31

2.33

0.98

GAUSSIAN 09 program package43. The fchk files

e

40.00

C1

12

2.700

35

2.32

1.36

produced by GAUSSIAN 09 are used as inputs for

f

50.99

Cs

6

2.448

42

2.29

1.67

44

Multiwfn 3.3.5 software

to analyze the electron

45

localization function (ELF) . Dimensional plots of the

a

Relative energy with respect to isomer A (-2918.7264 au) and a (-2918.8526 au) for Al12Be and Al12Be2–, respectively, at the CCSD(T)/aug-cc-pVDZ level.

molecular structures and the molecular orbital diagrams were generated with the GaussView program46.

3. RESULTS AND DISCUSSION 3.1. Geometric Characteristics of Al12Be and Al12Be2– We start by discussing the global minimum and low-lying isomers of Al12Be. Nine lower-energy isomers of Al12Be, named as A–I according to their increasing total energy order A < B < C < … at the CCSD(T)/aug-cc-pVDZ level, are illustrated in Figure 1. The important geometrical parameters, relative energies, binding energies per atom, and HOMO–LUMO gaps of these isomers are listed in Table 1.

Figure 1. Minimum energy structures of Al 12Be and their corresponding Al12Be2– clusters at the B3LYP/aug-cc-pVDZ level. The symmetry point groups are given in the parentheses and superscripts indicate spin multiplicity.

As shown in Figure 1, the D3d -symmetric global minimum structure A is a compact quasi-icosahedron with

Herein, the triplet state isomers D and F are similar in

the Be atom lying centrally, which is similar to those of

geometry to the singlet state A except that the C2v-

38–40

50

symmertic structure F is a little narrower. These two

etc.) clusters. The less favorable isomer B

isomers lie 5.35 and 8.28 kcal/mol in energy above the

possesses a Cs-symmetric structure, in which the Be atom

ground state A, respectively. In the last three isomers G-I,

caps the top of the Al12 framework. Each isomer of C-F

the Be atom locates outside the Al-cage. From Table 1,

exhibits a Be-centered capsule geometry where the Be

when the Be atom lies on the surface of the Al12 cluster, it

atom tends to bind with twelve neighboring Al atoms.

tends to bind with 5-6 Al atoms, and the average Al-Be

previously reported Al12M (M = Al, Co,

51

51

and Ni,

47

47

49

C, Si, N, P,



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 12

bond lengths are shorter by ca. 0.2 Å than those of the other

together in these clusters. As for Al12Be2–, their Eb values

isomers (A and C-F). It is noted that the framework of G is

(2.29–2.46 eV) are even larger than those of neutral Al12Be

analogous to that of B, only with a different location of Be

clusters, demonstrating the enhanced stability of these ani-

atom.

ons. Especially, the Eb value of isomer a is equal to that of

It is known that the chalcogens have a common oxidation state of -2, so we also obtained the equilibrium struc-

2.46 eV (computed at the same level) for the stable superatom anion Al13–.

tures of the Al12Be2– dianion. After the neutral Al12Be iso-

In metallic clusters, the HOMO–LUMO gap is

mers gain two additional electrons, only six optimized

generally indicative of stability and chemical inertness.28

structures namely a–f, were identified for the resulting

As shown in Table 1, all the neutral Al12Be clusters possess

2–

Al12Be

isomers (see Figure 1). Their relative energies,

large gap values of 1.14-2.25 eV. Note that the most stable

selected geometrical parameters, binding energies per atom,

Al12Be2– presents a pretty large HOMO-LUMO gap of 2.29

and HOMO–LUMO gaps are also summarized in Table 1.

eV, which is not only much larger than that of 1.57 eV for

From Figure 1, a perfect icosahedron conformation a with

the kinetically stable C60 in experiment,52 but also exceeds

Ih symmetry is found to be most stable among the six

that of 1.87 eV for its isoelectronic Al13–,53 suggesting its

Al12Be2– isomers. Note that a has a shorter average Be-Al

large chemical stability. Especially, this gap value is 0.73

bond length (2.622 Å, see Table 1) compared with its neu-

eV larger than that of its neutral parent Al12Be, implying

tral parent A. Hence, adding two electrons to structure A

that Al12Be tends to receive two electrons to reach a more

leads to a more compact geometry with higher symmetry.

stable electronic state, just as chalcogen species do.

This can be attributed to the closed shell electronic configu-

3.2. Quasi-chalcogen Characteristics

ration of isomer a. Isomer b is 19.85 kcal/mol higher in energy than isomer a. It has a sandwich structure with the Be atom staying at the center. The C5-symmetric structure c can be obtained from a by exchanging the positions of Be and an apex Al atom. The following triplet isomers d and e also possess Be-centered structures. Isomer d bears great structural similarity to isomer a, but has a lower D5d sym-

As we all know, all the chalcogen elements possess six valence electrons and have a tendency to accept two more electrons to complete the octet, especially oxygen. In chemistry, the capability of an atom or molecule to accept electrons is usually measured by electron affinity (EA). Therefore, it is meaningful to compare the electron affinity

metry. f, the least favorable Al12Be2– isomer here, features a

of the Al12Be superatom with those of chalcogens. The first

bi-capped pentagonal prism structure and is 50.99 kcal/mol

and second vertical electron affinities of the lowest-energy

less stable than a.

Al12Be cluster (a) were obtained at the CCSD(T)/aug-cc-

In order to measure the stability of these Al12Be and Al12Be2– clusters, we also obtained their binding energies per atom (Eb) at the CCSD(T)/aug-cc-pVDZ level, which are defined as,

pVDZ level, which are expressed as, 1st EA  E (Al12Be) - E (Al12Be- ) 2nd EA  E(Al12Be- ) - E(Al12Be2- )

Eb [Al12Be]  (12E[Al]  E[Be]  E[Al12Be])/13

where the E(Al12Be), E(Al12Be–), and E(Al12Be2–) are the

Eb [Al12Be2  ]  (10E[Al]  2E[Al ]  E[Be]  E[Al12Be2  ]/13

total energies of Al12Be as well as its anion and dianion,

The results are summarized in Table 1. As can be seen, the

respectively, calculated at the neutral geometry. It is

Eb values of neutral Al12Be clusters are as large as 2.11–

noteworthy that Al12Be exhibits a very large 1st EA value of

2.17 eV, which are nearly equal to that of 2.17 eV (com-

2.826 eV. This value is much higher than those (1.461–

puted at the same level) for the quasi-halogen Al13

2.077 eV)54 of chalcogens, but lower than those (3.059–

superatom,26 indicating that the atoms are tightly combined

3.617 eV)54 of halogens. It has been reported that the


Page 5 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


chalcogen elements have large negative second electron nd

55

affinities (2 EA) though they feature fairly positive first st

structures of (Al12Be)Lin (n = 1–5) are given in Figure S1. In Figure 2a and Table S1, we show the variation of the

54

electron affinities (1 EA) . Interestingly, the second

binding energies per atom (Eb), second difference in energy

electron affinity of Al12Be is also negative. However,

(2E), dissociation energies (E) of the (Al12Be)Lin (n = 1–

Al12Be has a less endothermic second EA (-0.545 eV) than

5) clusters at the CCSD(T)/aug-cc-pVDZ level, which are

those of oxygen (-8.164 eV),

55

sulfur (-6.123 eV),

55

55

and

nd

selenium (-6.259 eV). The discrepancy in 2 EA between Al12Be and chalcogen elements can be attributed to the larger size of Al12Be superatom, which helps to disperse

defined as, E b [( Al12 Be)Li n ]  12E[Al]  E[Be]  nE[Li]  E[( Al12 Be)Li n ]/[n  13]

E[( Al12Be)Li n ]  E[(Al12Be)Li n-1 ]  E[Li]  E[Al12BeLi n ]

extra negative charges and consequently reduce the

Δ2 E[(Al12Be)Li n ]  E[(Al12Be)Li n 1 ]  E[(Al12Be)Li n -1 ]  2E[(Al12Be)Li n ]

Coulomb repulsion. The more exothermic first EA and less

The magnitude of binding energy per atom gives in-

endothermic

second

EA

values

of

Al12Be

than

formation about the strength of chemical bonds in clusters,

corresponding those of chalcogens not only confirm the

thus the peaks for clusters of specific size signify their rela-

ability of Al12Be to gain two electrons from other species,

tive high stability. From Figure 2a, the (Al12Be)Li2 cluster

but also reflect its size advantage in this respect.

is particularly prominent in the Eb curve among the (Al12Be)Lin

series.

Note

that

remarkable

peak

at

(Al12Be)Li2 also appears in the E and  E evolution 2

curves, indicating its preferred formation from the growth of (Al12Be)Li or from the fragmentation of (Al12Be)Li3. To further explore the electronic stability of the (Al12Be)Lin (n = 1–5) series, the evolution of HOMO– LUMO gaps of (Al12Be)Lin has been examined at the B3LYP/aug-cc-pVDZ level. From Figure 2b, the gap curve shows a similar trend to those of Eb and E. What is intriguing is that the (Al12Be)Li2

cluster has an

extraordinarily large gap value of 2.45 eV, which again reveals its unusual stability and chemical inertness. From NBO analysis, there is electron transfer from Li atoms to Al12Be and the latter species carries -1.274|e| charge in the (Al12Be)Li2 cluster. Hence, the Al12Be cluster prefers to combine with two Li atoms to form a stable ionic compound, just as a chalcogen atom does. The electron localization function (ELF) of (Al12Be)Li2 is calculated and Figure 2. Evolutions of (a) binding energies per atom (Eb), second difference in energy (2E), dissociation energies (E) and (b) HOMO–LUMO gaps of the (Al12Be)Lin (n = 1–5) compounds.

compared with that of Al12Be in Figure 3. Differing from the metallic bonds in Al12Be, the ELF values for the area between Li and Al12Be in (Al12Be)Li2 are very small,

We then focused on several Al12Be-based compounds

indicating the existence of electrostatic force. Therefore,

and explored the behavior of Al12Be when combined with

the (Al12Be)Li2 is further confirmed to be an ionic

other atoms or clusters. Firstly, we considered the clusters

compound in which the superatomic Al12Be unit behaves

composed of Al12Be and lithium atoms. The optimized

like a chalcogen element.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 12

combine with atom of carbon to form a stable compound similar to CO or CS molecule. Besides, the total Wiberg bond index (WBI)57 of the bonds between Al12Be and C is 2.572, which is just in between those of 2.706 and 2.238 for the CS and CO molecules, respectively, at the same B3LYP/aug-cc-pVDZ level. Interestingly, the C atom Figure 3. Cut-plane ELF of the Al12Be, (Al12Be)Li2, and (Al12Be)Ca clusters.

seems to bind with Al12Be by a tight “triple bond”, which further confirms the similarity between Al12Be and

The quasi-chalcogen characteristics of Al12Be were al-

chalcogen atoms.

so confirmed by examining its combination with atoms in the second row of the periodic table. The initial structures of (Al12Be)M (M = Li, Be, B, C, N, O, and F) were constructed by randomly putting an M atom on the surface of structure A of Al12Be. Then the resulting geometries were optimized at the B3LYP/aug-cc-pVDZ level, and the lowest-energy structure of each (Al12Be)M species has been chosen and shown in Figure S2. From the figure, all the additional M atoms favor an external position except that the carbon atom is embedded inside the Al12Be framework. It is noted that the structural integrity of Al12Be is generally preserved in each (Al12Be)M compound. The dissociation energy (De) values of (Al12Be)M  Al12Be + M for these (Al12Be)M species were obtained at the CCSD(T)/aug-cc-pVDZ level by using the equation De  E[Al12Be]  E[M] - E[(Al12Be)M]

The calculated De values are collected in Table S2 and plotted in Figure 4a. For comparison, the experimental bond dissociation energies56 of diatomic MO and MS (M = Li, Be, B, C, N, O, and F) molecules are also illustrated in Figure 4a. Amazingly, significant similarity has been found

Figure 4. (a) Dissociation energies (De) and (b) HOMO–LUMO gaps of the (Al12Be)M (M = Li, Be, B, C, N, O, and F) compounds. The dissociation energies of diatomic MO and MS (M = Li, Be, B, C, N, O, and F) molecules are also illustrated.

between the dissociation energy curve of the (Al12Be)M

The HOMO-LUMO gap values of these (Al12Be)M

compound and those of MO and MS diatomic species. As

compounds are plotted in Figure 4b. As can be seen, the

shown in Figure 4a, the De values of these three systems

variation of these gap values presents an odd-even pattern.

firstly increase with the increasing atomic number of M

Remarkably, the Al12Be2 and (Al12Be)C compounds pos-

atoms, and reach a maximum value at M = C, then show a

sess considerable gap values of 2.68 and 2.22 eV, respec-

downtrend. Note that the (Al12Be)C cluster possesses the

tively. The prominent stability of (Al12Be)Be can be at-

largest De value among these (Al12Be)M compounds, just

tributed to its “magic” valence electron number of 40. As

as carbon monoxide (CO) and carbon monosulfide (CS)

for (Al12Be)C, its large gap value may relate to its similari-

have the largest De among MO and MS diatomic molecules,

ty to the highly stable CO or CS molecule as pointed out

respectively. This indicates that the Al12Be superatom can

above.


Page 7 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


The aforementioned exciting findings motivate us to

Another counterion chosen for the Al12Be2– dianion is

move forward to detect the resemblance between Al12Be-

FLi32+,58 which can be considered as a superalkaline-earth

based compounds and typical oxides/sulfides. Firstly, we

dication. Several initial structures of (Al12Be)FLi3 were

considered the combination of Al12Be and calcium atom.

constructed by attaching FLi32+ to the surface of Al12Be2– (a)

As shown in Figure 5, the global minimum of (Al 12Be)Ca

at different positions and orientations. As a result of geom-

has a capped geometry, which is similar to those of

etry optimization, a C3v-symmetric equilibrium structure

57

(Al12Be)Be and (Al12Be)Li. NBO analysis shows that the

with the FLi3 subunit capping one Al3-face of Al12Be is

Al12Be unit carries an effective charge of -1.468|e|, which is

obtained at the B3LYP/aug-cc-pVDZ level. From Figure 5,

close to the S charge of -1.408|e| in CaS and O charge of -

both Al12Be and FLi3 moieties retain their structural integri-

1.522|e| in CaO. The ELF of (Al12Be)Ca also verifies the

ty during the superatom-superatom interaction. Besides, it

ionic bond formation between Ca and Al12Be, just like the

is interesting to find that the Al12Be superatom prefers to

case in (Al12Be)Li2 mentioned above (see Figure 3). The

bind with Li atoms instead of the electronegative F atom of

total Wiberg bond index of the bonds between Ca and

FLi3, showing its “non-metallic” feature and tendency to

Al12Be is 0.974, which is in good accordance with those of

gain electrons. In this respect, NBO analysis provides fur-

1.017 for Ca-S bond in CaS and 0.864 for Ca-O bond in

ther evidence. An effective charge of -1.455|e| on the

CaO. In addition, the (Al12Be)Ca

exhibits

Al12Be subunit indicates that the combination of Al12Be

considerable chemical stability in view of its large HOMO-

and FLi3 finally results in an ionic superatom compound

LUMO gap of 2.33 eV. Therefore, it can be concluded that

(Al12Be)2–(FLi3)2+, mimicking the CaO molecule. Similarly,

Al12Be shows chemical behavior similar to a chalcogen

the total Wiberg bond index (0.746) of the bridge Al-Li

atom when interacting with Ca atom, leading to a stable

bonds is comparable to that of Ca-O bond (0.864) in the

CaO-like ionic compound.

CaO molecule.

cluster

Next the dissociation energies (De) of (Al12Be)Ca  Al12Be + Ca and (Al12Be)FLi3  Al12Be + FLi3 channels were calculated by using the CCSD(T) method in conjunction with the same basis sets used in structural optimizations. Herein, we used the counterpoise procedure59 to eliminate the basis set superposition error (BSSE) effect.60 As can be expected from the quasi-chalcogen character of Al12Be, both superatom compounds exhibit high stability toward dissociation. The dissociation energy (De) of (Al12Be)Ca is as large as 78.4 kcal/mol, which is comparable to those of CaO and CaS molecules, namely 91.7 kcal/mol56 and 80.1 kcal/mol56 measured in experiments. Note that (Al12Be)FLi3 has a much larger De value of 135.9 kcal/mol as a result of multiple bonds between the FLi3 and Al12Be superatoms (see Figure 5). The large dissociation energies of (Al12Be)Ca and (Al12Be)FLi3 demonstrate that Figure 5. Optimized geometrical structures of (Al12Be)Ca, (Al12Be)FLi3, and triplet (Al12Be)2 dimer.

the Al12Be cluster has the ability to bind tightly with (super)alkaline-earth metal counterparts and generate stable superatom compounds resembling the CaO/CaS molecules.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 12

Now that the Al12Be cluster behaves as a chalcogen

was indicated to be stable up to 150 K in computer simula-

atom when combined with other (super)atoms, it is reason-

tions.61 NBO analysis shows that the total Wiberg bond

able to consider the possibility of obtaining an (Al12Be)2

index (WBI) of the three bridged Al-Al bonds in (Al12Be)2

dimer reminiscent of the dioxygen or disulfur molecule. To

is 1.195, which is smaller than those of 1.504 and 1.502 for

locate the ground state of (Al12Be)2 dimer, we first com-

O2 and S2 molecules at the B3LYP/aug-cc-pVDZ level,

bined two Al12Be monomers via different bonding orienta-

respectively. This discrepancy may be attributed to the fact

tions, and then optimized these designed structures with

that the chemical bond between the two Al12Be subunits is

spin multiplicities of 1 and 3, respectively. Two similar

metallic while those of the traditional O2 and S2 molecules

conformers with different spin states have been obtained at

are covalent.

the B3LYP/aug-cc-pVDZ level. Similar to the triplet dioxygen and disulfur molecules, the (Al12Be)2 dimer also

3.3. Origin of the Quasi-chalcogen Characteristcs of Al12Be

possesses a triplet ground state (see Figure 5), which is lower in energy than the singlet one (see Figure S3) by

Based on the above discussion, there are significant

2.147 kcal/mol with zero-point vibrational energy (ZPVE)

evidences pointing to the similarity between the Al12Be

correction. From Figure 5, it can be seen that the two Al12Be subunits are linked by three Al-Al bonds of 2.61 Å. Interestingly, this bond length is a little shorter than the average Al-Al bond length (2.751 Å) within each Al12Be unit, suggesting that the two Al12Be moieties are tightly bound together. Besides, the calculated dissociation energy (De) with ZPVE correction of (Al12Be)2  2Al12Be is as large as 80.6 kcal/mol at the B3LYP/aug-cc-pVDZ level, which is somewhat less than but comparable to those of O2 (ca. 119 kcal/mol)56 and S2 (ca. 102 kcal/mol)56. Note that the dissociation energy of (Al12Be)2 is even larger than that of 69.9 kcal/mol for the (Al3H)2 dimer, whose cluster solid

cluster and chalcogen elements. Then, one may wonder what is the source of the quasi-chalcogen characteristics of Al12Be. To elucidate this question, we analyzed the valence molecular orbitals (MOs) of the most stable Al12Be (isomer A), Al12Be2– (isomer a) and (Al12Be)Li2 species based on the electronic counting rule and shell model. The Al12Be cluster has 38 valence electrons coming from Al and Be sites (each Al atom contributes three and the Be atom contributes two valence electrons). As shown in Figure 6, the lowest state of Al12Be has 1S character. The next three states have typical P character and are followed by five 1D orbitals. The set of D orbitals is followed

Figure 6. The valence molecular orbitals (MOs) of the most stable Al12Be, Al12Be2– and (Al12Be)Li2 clusters (isovalue = 0.02). For each level of Al12Be and Al12Be2–, the degeneracy has been marked. At the bottom of each picture, the electronic shell structure of the cluster is displayed.


Page 9 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


by a 2S orbital. These states are followed by four 1F states

tomic oxides and sulfides, the similarity between Al12Be-

and two P states. The remaining three states show dominant

(super)alkaline-earth compounds and CaO/CaS molecules,

F character. In brief, the electronic structure of Al12Be is

and by the formation of O2/S2-like (Al12Be)2 dimer. The

1S21P61D102S21F82P41F6. Hence, similar to a chalcogen

extraordinary similarity between Al12Be and chalcogen

atom, Al12Be longs for two extra electrons to fill the unoc-

elements can be rationalized by its unique electronic struc-

cupied 2P molecular orbital (LUMO) and achieve an elec-

ture. To be specific, the driving force for 38-valence elec-

tron closed shell. Nevertheless, unlike the chalcogens hav-

tron Al12Be to attain two additional electrons and achieve a

ing degenerate outermost p orbitals, the nonspherical crys-

closed electron shell is the origin of its quasi-chalcogen

tal field originating from the lower symmetry of Al12Be

characteristics. The present study introduces Al12Be as a

leads to 2P orbital splitting. Since the electrons prefer to fill

new member to the 3D periodic table and consequently,

the lower energy level first, the Al12Be cluster does not

gives further backing to the superatom chemistry.

possess a triplet ground state as the chalcogens do. As for Al12Be2–, with two additional electrons, its MOs show a typical closed shell electronic configuration of 1S21P61D102S21F142P6, which is completely consistent with the spherical jellium model (SJM)13,14 and makes Al12Be2– a “magic” cluster. This reveals that Al12Be indeed achieves electronic shell closure upon gaining two electrons, just like chalcogens. Finally, the MOs of (Al12Be)Li2 are ana-

Supporting Information Optimized structures of the (Al12Be)Lin (n = 1–5), (Al12Be)M (M = Li, Be, B, C, N, O, and F), and the singlet (Al12Be)2 dimer; Binding energies per atom (Eb), second difference in energy (2E), dissociation energies (E) and HOMO–LUMO gaps of the (Al12Be)Lin (n = 1–5) compounds; Dissociation energies (De) and HOMO–LUMO gaps of the (Al12Be)M (M = Li, Be, B, C, N, O, and F) compounds. Cartesian coordinates of the Al12Be and Al12Be2– clusters. This material is available free of charge via the Internet at http://pubs.acs.org.

lyzed and the electronic structure of (Al12Be)Li2 is found to be 1S21P61D102S21F102P21F22P41F2, filled with 40 valence electrons. It can be seen that all the electron shells of

Corresponding Author

(Al12Be)Li2 are closed but slightly disordered due to the

* E-mail address: [email protected] Phone: +86-043181707218

existence of Li counterions. According to the SJM,13,14 this

Author Contributions

cluster with shell closure should exhibit special stability,

All authors have given approval to the final version of the manuscript.

justifying its exceptional behavior among the (Al12Be)Lin (n = 1-5) series. Based on the above analysis, the driving

Al12Be cluster have been systemically studied in this con-

This work was supported by the National Natural Science Foundation of China (21173095, 21573089, 21303066, 21375017, 21573089), State Key Development Program for Basic Research of China (2013CB834801), the Key Project of Fujian Science and Technology (2013Y0045), the National Science Foundation for Distinguished Young Scholars of Fujian Province (2013J06003), the Foundation of Fuzhou Science and Technology Bureau (2013S-122-4), the Medical Elite Cultivation Program of Fujian P.R.C (2014-ZQN-ZD-26), and the financial support of Fujian Medical University (JS14009).

tribution. The superatom identity of Al12Be is substantiated

REFERENCES

force to attain a closed electron shell is the origin of the quasi-chalcogen characteristics of Al12Be.

4. CONCLUSIONS In summary, the quasi-chalcogen characteristics of the

not only by its stability and large electron affinity, but also by the prominent behavior of (Al12Be)Li2 among the (Al12Be)Lin series, the large HOMO-LUMO gaps of (Al12Be)Be and (Al12Be)C among the (Al12Be)M (M = Li, Be, B, C, N, O, and F) compounds, the accordance of dis-

(1) Khanna, S.; Jena, P. Assembling Crystals From Clusters. Phys. Rev. Lett. 1992, 69, 1664 -1667. (2) Khanna, S.; Jena, P. Atomic Clusters: Building Blocks for a Class of Solids. Phys. Rev. B 1995, 51, 13705-13716. (3) Castleman, A. W. From Elements to Clusters: The Periodic Table Revisited. J. Phys. Chem. Lett. 2011, 2, 1062 -1069. (4) Jena, P. Beyond the Periodic Table of Elements: The Role of Superatoms. J. Phys. Chem. Lett. 2013, 4, 1432 -1442.

sociation energy evolution of (Al12Be)M with those of dia-



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(5) Reber, A. C.; Khanna, S. N.; Castleman, A. W. Superatom Compounds, Clusters, and Assemblies: Ultra Alkali Motifs and Architectures. J. Am. Chem. Soc. 2007, 129, 10189-10194. (6) Li, Y.; Wu, D.; Li, Z. R. Compounds of Superatom Clusters: Preferred Structures and Significant Nonlinear Optical Properties of the BLi6-X (X = F, LiF2, BeF3, BF4) Motifs. Inorg. Chem. 2008, 47, 9773-9778. (7) A. W. Castleman, J.; Khanna, S. N. Clusters, Superatoms, and Building Blocks of New Materials. J. Phys. Chem. C 2009, 113, 2664-2675. (8) Clayborne, P.; N.O. Jones; A.C. Reber; Reveles, J. U.; Qian, M. C.; Khanna, S. N. Superatoms and Their Assemblies Based on Alkali and Super-alkali Motifs. J. Comput. Methods Sci. Eng. 2007, 7, 417-430. (9) Claridge, S. A.; A. W. Castleman, J.; Khanna, S. N.; Murray, C. B.; Sen, A.; Weiss, P. S. Cluster-Assembled Materials. ACS Nano 2009, 3, 244-255. (10) Qian, M.; Reber, A. C.; Ugrinov, A.; Chaki, N. K.; Mandal, S.; Hector M. Saavedra; Khanna, S. N.; Sen, A.; Weiss, P. S. ClusterAssembled Materials: Toward Nanomaterials with Precise Control over Properties. ACS Nano 2010, 4, 235-240. (11) Mandal, S.; Reber, A. C.; Qian, M.; Weiss, P. S.; Khanna, S. N.; Sen, A. Controlling the Band Gap Energy of Cluster-Assembled Materials. Acc. Chem. Res. Acc. Chem. Res. 2013, 46 (11), 23852395. (12) Giri, S.; Behera, S.; Jena, P. Superalkalis and Superhalogens as Building Blocks of Supersalts. J. Phys.Chem. A 2014, 118, 638645. (13) Ekardt, W. Work Function of Small Metal Particles: SelfConsistent Spherical Jellium-background Model. Phys. Rev. B 1984, 29, 1558-1564. (14) Knight, W. D.; Clemenger, K.; de Heer, W. A.; Saunders, W. A.; Chou M. Y.; Cohen M. L. Electronic Shell Structure and Abundances of Sodium Clusters. Phys. Rev. Lett. 1984, 52, 2141-2143. (15) Gutsev, G. L.; Boldyrev, A. I. DVM X-α Calculations of the Electronic-structure of “Superalkali” Cations. Chem. Phys. Lett. 1982, 92, 262-266. (16) Gutsev, G. L.; Boldyrev, A. I. DVM X-α Calculations on the Ionization Potentials of Complex Anions and the Electron Affinities of MXk+1 “Superhalogens”. Chem. Phys. 1981, 56, 277-283. (17) Wu, M. M.; Wang, H.; Ko, Y. J.; Wang, Q.; Sun, Q.; Kiran, B.; Kandalam, A. K.; Bowen, K. H.; Jena, P. Manganese-Based Magnetic Superhalogens. Angew. Chem. Int. Ed. 2011, 50, 25682572. (18) Ko, Y. J.; Wang, H.; Pradhan, K.; Koirala, P.; Kandalam, A. K.; Bowen, K. H.; Jena, P. Superhalogen Properties of CumCln Clusters: Theory and Experiment. J. Chem. Phys. 2011, 135, 244312. (19) Wang, D.; Graham, J. D.; Buytendyk, A. M.; Bowen, K. H. Photoelectron Spectroscopy of the Molecular Anions, Li3O− and Na3O−. J. Chem. Phys. 2011, 135, 164308. (20) Gutsev, G. L.; Khanna, S. N.; Rao, B. K.; Jena, P. FeO4 A Unique Example of a Closed-shell Cluster Mimicking a Superhalogen. Phys. Rev. A 1998, 59, 3681-3684. (21) Wang, Q.; Sun, Q.; Jena, P. Superhalogen Properties of CuFn Clusters. J. Chem. Phys. 2009, 131, 124301. (22) Samanta, D.; Wu, M. M.; Jena, P. Au(CN)n Complexes: Superhalogens with Pseudohalogen as Building Blocks. Inorg. Chem. 2011, 50, 8918-8925. (23) Tong, J.; Li, Y.; Wu, D.; Li, Z. R.; Huang, X. R. Low Ionization Potentials of Binuclear Superalkali B2Li11. J. Chem. Phys. 2009, 131, 164307. (24) Sun, W.-M.; Li, Y.; Wu, D.; Li, Z.-R. Designing Aromatic Superatoms. J. Phys.Chem. C 2013, 117, 24618-24624. (25) Hou, N.; Wu, D.; Li, Y.; Li, Z. R. Lower the Electron Affinity by Halogenation: an Unusual Strategy to Design Superalkali Cations. J. Am. Chem. Soc. 2014, 136, 2921-2927. (26) Bergeron, D. E.; Jr., A. W. C.; Morisato, T.; Khanna, S. N. Formation of Al13I-: Evidence for the Superhalogen Character of Al13. Science 2004, 304, 84-87.

Page 10 of 12

(27) Bergeron, D. E.; Roach, P. J.; Jr., A. W. C.; Jones, N. O.; Khanna, S. N. Al Cluster Superatoms as Halogens in Polyhalides and as Alkaline Earths in Iodide Salts. Science 2005, 307, 231-235. (28) Reveles, J. U.; Khanna, S. N.; Roach, P. J.; Castleman, A. W. Multiple Valence Superatoms. Proc. Natl. Acad. Sci. USA. 2006, 103, 18405-18410. (29) Reveles, J. U.; Baruah, T.; Zope, R. R. Al12Cu Superatom as Stable Building Block of Ionic Salts. J. Phys. Chem. C 2015, 119, 5129-5137. (30) Kumar, V.; Kawazoe, Y. Metal-doped Magic Clusters of Si, Ge, and Sn: The Finding of a Magnetic Superatom. Appl. Phys. Lett. 2003, 83, 2677-2679. (31) Reveles, J. U.; Clayborne, P. A.; Reber, A. C.; Khanna, S. N.; Pradhan, K.; Sen, P.; Pederson, M. R. Designer Magnetic Superatoms. Nat. Chem. 2009, 1, 310-315. (32) Pradhan, K.; Reveles, J. U.; Sen, P.; Khanna, S. N. Enhanced Magnetic Moments of Alkali Metal Coated Sc Clusters: New Magnetic Superatoms. J. Chem. Phys. 2010, 132, 124302. (33) Reveles, J. U.; Sen, P.; Pradhan, K.; Roy, D. R.; Khanna, S. N. Effect of Electronic and Geometric Shell Closures on the Stability of Neutral and Anionic TiNa n (n = 1-13) Clusters. J. Phys. Chem. C 2010, 114, 10739-10744. (34) Medel, V. M.; Reveles, J. U.; Khanna, S. N.; Chauhan, V.; Sen, P.; Castleman, A. W. Hund's Rule in Superatoms with Transition Metal Impurities. Proc. Natl. Acad. Sci. USA. 2011, 108, 1006210066. (35) Chauhan, V.; Medel, V. M.; Ulises Reveles, J.; Khanna, S. N.; Sen, P. Shell Magnetism in Transition Metal Doped Calcium Superatom. Chem. Phys. Lett. 2012, 528, 39-43. (36) Medel, V. M.; Reveles, J. U.; Islam, M. F.; Khanna, S. N. Shell Magnetism in Transition Metal Doped Calcium Superatom. J. Phys. Chem. A 2013, 117, 4297-4303. (37) Zhang, X.; Wang, Y.; Wang, H.; Lim, A.; Gantefoer, G.; Bowen, K. H.; Reveles, J. U.; Khanna, S. N. On the Existence of Designer Magnetic Superatoms. J. Am. Chem. Soc. 2013, 135, 48564861. (38) Chuang, F.-C.; Wang, C.; Ho, K. Structure of neutral aluminum clusters Aln (2 ≤ n ≤ 23): Genetic algorithm tight-binding calculations. Phys. Rev. B 2006, 73, 125431. (39) Li, Z. H.; Jasper, A. W.; Truhlar, D. G. Structures, Rugged Energetic Landscapes, and Nanothermodynamics of Aln (2≤ n ≤ 65) Particles. J. Am. Chem. Soc. 2007, 129, 14899-14910. (40) Lu, W.-C.; Wang, C. Z.; Zhao, L.-Z.; Zhang, W.; Qin, W.; Ho, K. M. Appearance of bulk-like motifs in Si, Ge, and Al clusters. Phys. Chem. Chem. Phys. 2010, 14, 8551-8556. (41) Saunders, M. Stochastic Search for Isomers on a Quantum Mechanical Surface. J. Comput. Chem. 2004 25, 621-626. (42) Reed, A. E.; Weinstock, R. B.; Weinhold, F. Natural Population Analysis. J. Chem. Phys. 1985, 83, 735-746. (43) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani G.; Barone V.; Mennucci B.; Petersson G. A. et al. GAUSSIAN 09, Revision A02, Gaussian, Inc., Wallingford CT, 2009. (44) Lu, T.; Chen, F. Multiwfn: a Multifunctional Wavefunction Analyzer. J. Comput. Chem. 2012, 33, 580 -592. (45) Becke, A. D.; Edgecombe, K. E. A Simple Measure of Electron Localization in Atomic and Molecular Systems. J. Chem. Phys. 1990, 92, 5397-5403. (46) Dennington, R.; Keith, T.; Millam, J. GaussView, Version 5, Semichem Inc., Shawnee Mission, KS, 2009. (47) Chandrachud, P.; Joshi, K.; Kanhere, D. Thermodynamics of Carbon-doped Al and Ga Clusters: Ab Initio Molecular Dynamics Simulations. Phys. Rev. B 2007, 76, 235423. (48) Li, S.; Gong, X. Neutral and Negatively Charged Al12X (X=Si, Ge, Sn, Pb) Clusters Studied From First Principles. Phys. Rev. B 2006, 74, 045432. (49) Wang, B.; Zhao, J.; Shi, D.; Chen, X.; Wang, G. Densityfunctional Study of Structural and Electronic Properties of AlnN(n=2-12) Clusters. Phys. Rev. A 2005, 72, 023204.


Page 11 of 12

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(50) Guo, L.; Wu, H. Density Functional Study of Structural and Electronicproperties of AlnP (2 ≤ n ≤12) clusters. J. Nano. Res. 2008, 10, 341–351.

(51) Wang, M.; Huang, X.; Du, Z.; Li, Y. Structural, Electronic, and Magnetic Properties of a Series of Aluminum Clusters Doped with Various Transition Metals. Chem. Phys. Lett. 2009, 480, 258 -264. (52) Wang, X.-B.; Ding, C.-F.; Wang, L.-S. High Resolution Photoelectron Spectroscopy of C60-. J. Chem. Phys. 1999, 110, 82178220. (53) Khanna, S.; Rao, B.; Jena, P. Electronic Signature of the Magicity and Ionic Bonding in Al13X (X=Li-K) Clusters. Phys. Rev. B 2002, 65, 125105. (54) Hotop, H.; Lineberger, W. C. Binding Energies in Atomic Negative Ions. II. J. Phys. Chem. Ref. Data 1985, 14, 731-750. (55) Guo, Y.; Whitehea, M. A. Calculation of the Second Electron Affinities of Atoms. Can. J. Chem. 1990, 68, 1585-1589. (56) Luo, Y .R . Comprehensive Handbook of Chemical Bond Energies, CRC Press, 2007. (57) Glendening, E. D.; Badenhoop, J. K.; Reed, A. E.; Carpenter, J. E.; Bohmann, J. A.; Morales, C. M.; Landis, C. R.; Weinhold, F. NBO 6.0; University of Wisconsin: Madison, WI, 2013. (58) Elliott, B. M.; Boldyrev, A. I. Ozonic Acid and Its Ionic Salts: Ab Initio Probing of the O42- Dianion. Inorg. Chem. 2004, 43, 4109-4111. (59) Boys, S. F.; Bernardi, F. The Calculation of Small Molecular Interactions by the Differences of Separate Total Energies. Some Procedures with Reduced Errors. Mol. Phys. 1970, 19, 553-566. (60) Alkorta, I.; Elguero, J. The Calculation of Small Molecular Interactions by the Differences of Separate Total Energies. Some Procedures with Reduced Errors. J. Phys. Chem. A 1999, 103, 272-279. (61) Duque, F.; Mañanes, A.; Molina, L. M.; López, M. J.; Alonso, J. A. Computer simulation of cluster assembling. Int. J. Quantum Chem. 2002, 86(2), 226-238.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 12

.

For Table of Contents Only Synopsis: A novel superatom with quasi-chalcogen characteristics is proposed as a new member of the three-dimentional periodic table.


Quasi-Chalcogen Characteristics of Al12Be: A New Member of the

Recommend Documents