Theoretical Study on the Photoelectron Spectra of Ln(COT)2

Subscriber access provided by University of Otago Library

Article 2-

Theoretical Study on the Photoelectron Spectra of Ln(COT) : Lanthanide Dependence of the Metal-Ligand Interaction Erika Nakajo, Tomohide Masuda, and Satoshi Yabushita J. Phys. Chem. A, Just Accepted Manuscript • DOI: 10.1021/acs.jpca.6b10930 • Publication Date (Web): 02 Nov 2016 Downloaded from http://pubs.acs.org on November 6, 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 A 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 48

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

Theoretical Study on the Photoelectron Spectra of Ln(COT)2−: Lanthanide Dependence of the Metal-Ligand Interaction Erika Nakajo, Tomohide Masuda, and Satoshi Yabushita* Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

Abstract We have performed a theoretical analysis of the recently reported photoelectron (PE) spectra

of

the

series

of

sandwich

complex

anions

Ln(COT)2−

(Ln=La-Lu,

COT=1,3,5,7-cyclooctatetraene), focusing on the Ln dependence of the vertical detachment energies. For most Ln, the π molecular orbitals, largely localized on the COT ligands, have the energy order of e1g < e1u < e2g < e2u as in the actinide analogues, reflecting the substantial orbital interaction with the Ln 5d and 5p orbitals. Thus, it would be expected that the lanthanide contraction would increase the orbital interaction so that the overlaps between the COT π and Ln atomic orbitals tend to increase across the series. However, the PE spectra and theoretical calculations were not consistent with this expectation, and the details have been clarified in this study. Furthermore, the energy level splitting patterns of the anion and neutral complexes have been studied by multireference ab initio methods, and the X peak splittings observed in the PE spectra only for the middle-range Ln complexes were found to be due to the specific interaction between the Ln 4f and ligand π orbitals of the neutral complexes in e2u symmetry. Since the magnitude of this 4f-ligand interaction depends critically on the final state 4f electron configuration and the spin state, a significant Ln dependence in the PE spectra is explained. Keywords: lanthanide organometallic complex, lanthanide contraction, metal-ligand interaction, ionic bonding, 4f orbital

1

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

1. Introduction Lanthanides (Ln) have received considerable attention for many years because of their great potential in various applications to magnetic and optical materials, superconductors, catalysts, and control materials for reactors etc. The chemical uniqueness of this series is mainly due to the localized 4f electrons, which are shielded from the chemical environment by the outer 5s and 5p electrons. Partial occupancy of the 4f orbitals and the common outer closed-shell 5s25p6 shells are the origin of the chemical and physical similarity of the Ln series, and also of a monotonic decrease of the ionic radius with increasing the atomic number (AN). The latter phenomenon, known as the lanthanide contraction, mainly arises from the incomplete shielding of the nuclear charge by the 4f electrons.1,2 In organometallic chemistry, organolanthanides have attracted attention for their special features.3-9 Especially, after the synthesis of bis(cyclooctatetraenyl)uranium U(COT)2 by Streitwieser and Müller-Westerhoff in 1968,10 f-element complexes with the COT ligands have been one of the most fascinating systems with novel coordination and a new type of metal-ligand interaction. Along with the syntheses of a number of Ln-COT complexes, for example, Eu(COT) and Yb(COT),11 potassium salts Ln(COT)2K for various Ln,12 and cerocene Ce(COT)2,13 the experimental investigations of these geometric structures and their chemical properties14-19 revealed a highly ionic bonding character. Since the COT ligand gains aromaticity with two excess π electrons, the anion complex Ln(COT)2− is stable for typical trivalent Ln elements. These complexes have a highly symmetric D8h structure with two planer parallel COT2− rings sandwiching the Ln3+ ions. On the other hand, EuIII(COT)2− and YbIII(COT)2− are not synthesized because of the tendency of Eu and Yb to be in the +2 oxidation state.12 Ln(COT)2− is an important synthetic unit in forming the one-dimensional multiple-decker complexes Lnn(COT)m, which have been produced by laser vaporization and molecular beam methods, and analyzed with spectroscopic methods20-24 as well as by Na atom doping.25 These regularly-arranged multiple-decker sandwich complexes with Ln metals 2


Page 2 of 48

Page 3 of 48

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


are expected to have the function of one-dimensional magnetic materials.26-28 Additionally, DFT based studies on the Eun(COT)n (n=1-4) anion23 and neutral24 complexes have elucidated the importance of the intracomplex electrostatic effect on the vertical detachment energies (VDEs). As is well known, there are a number of difficulties associated with quantum chemical calculations of f-element compounds, due to relativistic effects, strong electron correlation, and the partially occupied f orbitals. Therefore, detailed study of the simple complexes is of significant importance for understanding the complicated electronic structure of the complexes containing more than one f metal. As a precedent study for Lnn(COT)m, the electronic structures of the anion and neutral complexes Ln(COT)229-36 and those of the actinide (An) complexes An(COT)232-49 have been extensively investigated, with special emphasis on the participation of the d and f orbitals in the chemical bonding. For An(COT)2, the photoelectron (PE) spectroscopic studies38,40,42 and many DFT,33-34,39,41,46-48 semiempirical,45 and ab initio35,36,43,49 calculations revealed particularly the large participation of the 6de2g orbitals and the smaller participation of the 5fe2u orbitals. In contrast, for the Ln analogues, the semiempirical30 and the ab initio calculations31,35,36 have elucidated the considerably smaller involvement of the 4fe2u orbitals in the metal-ligand bonding, which results in more ionic character15 due to the more core-like nature of the 4f-shell; the greater radial extent and higher energy of the 5f orbitals of An complexes are more suitable for the interaction with the ligand π orbitals.36,50 In fact, it is a common belief that the Ln 4f orbitals are not involved in the metal-ligand covalency,51-53 unless a coincidental energy match occurs with the interacting ligand orbitals.54,55 Furthermore, in relation to the interaction between the 4f and ligand electrons, Neumann and Fulde proposed that the ground state of Ce(COT)2 may be a molecular analogue of a Kondo system, in which the unpaired 4f and ligand π orbitals are coupled to yield an open-shell singlet ground state. 56 The multiconfigurational studies for cerocene35,57-59 confirmed the singlet ground state and the mixing between the primary 4fe2u1πe2u3 and secondary 4fe2u0πe2u4 configurations. Additional 3



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

experimental evidence supporting the unusual ground state structure of cerocene61-63 was obtained, for example, by X-ray absorption near-edge structure (XANES) studies and magnetic measurements. Calculations for the other series31,36 have suggested that the corresponding configuration interaction occurs in the lighter Ln(COT)2 ground states, but the magnitude of the coupling decreases across the Ln series, because of the increasing core-like character of the 4f shell. These studies have indicated that the interaction between the 4f and ligand π electrons play an important role in both the chemical reactivity and in the magnetic properties of Ln(COT)2. A comprehensive investigation of the electronic structure of Ln(COT)2, anion PE spectra for Ln(COT)2− (excluding Eu, Yb, and radioactive Pm) and their theoretical investigation was recently published by Hosoya et al.64 The present paper gives further details of the theoretical part of the previous work64 and has two goals. First, we elucidate the Ln dependence of the metal-ligand interaction in terms of the orbital energies and overlaps. We give the quantitative description of the metal-ligand orbital interaction based on the second-order perturbative theory. Second, we provide the systematic investigation of the muticonfigurational electronic structures of the neutral complexes to give a complete description of the unusual interaction between the 4f and ligand π electrons for the whole Ln series. We compare the energy splittings of the anion and neutral complexes, and show particular splitting patterns in the neutral complexes, caused by the 4f-ligand interaction in e2u symmetry. Along with the dipole selection rule, it gives more accurate and sound description of the peak splittings in the anion PE spectra, and complements our previous DFT study on the Gd and Tb complexes. Although the spectra of the Eu(COT)2− and Yb(COT)2− were significantly different from those of the other Ln(COT)2−,20 we have also investigated these complexes, assuming the formal charge Ln3+(COT2−)2 and thus the D8h symmetric structures, as in the other Ln(COT)2−.

2. Calculational Methods The effective core potentials (ECPs) with the 46-electron core and the basis sets 4


Page 4 of 48

Page 5 of 48

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


(6s6p3d7f)/[4s4p2d2f] by Cundari and Stevens65 were used to represent the 5s, 5p and 4f valence shell electrons of Ln=Ce-Lu ((9s9p5d)/[4s4p3d] for Ln=La), and the D95(d) basis set66 ((9s5p1d)/[4s2p1d] for C and (4s)/[2s] for H) was used for COT. The open-shell state-averaged self-consistent field (SA-SCF) method was employed to obtain the orbital energies of the symmetry-adapted valence molecular orbitals (MOs), and the VDEs were derived with Koopmans’ theorem. In the SA-SCF method, the energy functional to be optimized is the average energy of the degeneracy weighted combination of the highest spin states with 4fn configurations.67 In the case of the Pr (4f2) complex, for example, the SA-SCF calculation has been optimized for the average energy of the atom-like 3H, 3F, and 3P states weakly perturbed by the presence of the COT ligands and each 4f dominated SCF orbital is equally occupied by 2/7 electrons. It coincides with the closed-shell Hartree-Fock method for the La and Lu complexes, for which n=0 and 14, respectively. This treatment has little effect on the valence π MOs because they have negligibly small contributions from the 4f orbitals, but note that Koopmans’ theorem in these cases is in general valid in an average sense, i.e., the negative of the orbital energies are equal to the VDEs averaged over all the highest spin configurations with the same 4fn occupation. To evaluate the X peak splittings, the state-averaged complete active space SCF (SA-CASSCF) calculations were followed by the second-order multi-configuration quasi-degenerate perturbation theory (MCQDPT2) calculations. For the MCQDPT2 calculations, an energy denominator shift value of 0.02 hartree was employed to avoid intruder state problems.68 The GAMESS program package69 was used for the SA-SCF, SA-CASSCF and MCQDPT2 calculations. The Ln(COT)2− structures were determined in D8h symmetry, by the DFT method with the B3LYP functionals70 using the Gaussian 09 program package.71 The large core (4f core) ECPs with the 46-60 electron cores and (7s6p5d)/[5s4p3d] basis sets of the Stuttgart/Cologne group72 were used for Ln, and the 6-31+G(d) basis set for COT were employed for the geometry optimization.

5



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

3. Results and Discussion 3-1. Lanthanide Dependence of Metal-Ligand Orbital Interaction. Figure 1 shows the optimized distances between Ln and the center of the COT carbon ring. Across the Ln series, only the Ln-COT distance shows a notable change, i.e., a steady decrease, due to the lanthanide contraction, of the Ln3+ ionic radius. The change rate of the distance versus AN of Ln is -0.0188 Å. In this paper, the change rates versus AN of Ln are defined as the slopes of the least squares fitted lines. Figure 2 presents the orbital interaction diagram for the valence MOs of Gd(COT)2−. Note that the valence orbitals are labelled based on the irreducible representations (irreps) in D8h symmetry. We first focus on the valence π orbitals largely localized on the ligands. Ten π electrons in each COT2− occupy the a2u, e1g, and e2u symmetry orbitals in order of increasing energy. The two a2u orbitals form two group orbitals in the double ring COT24−; in-phase πa1g and out-of-phase πa2u orbitals. Similarly, the two e1g orbitals form two group orbitals; in-phase πe1u and out-of-phase πe1g orbitals as displayed on the left side, and the combinations of the two e2u HOMOs form both in-phase πe2g and out-of-phase πe2u group orbitals, which are primarily involved in the metal-ligand interaction. Considering their orbital interaction with the valence Gd atomic orbitals for each irrep, the filled Gd 5p orbital contributes to the e1u MO in an anti-bonding manner, and the vacant 5d orbitals contribute to the e1g and e2g MOs in a bonding manner, as displayed in the portion of Gd(COT)2− in the middle of Figure 2. The 4f orbitals slightly contribute to the e2u and e1u MOs, but are safely ignored in this diagram. The MO energy order for Gd(COT)2− was calculated to be a1g < a2u of the Ln atomic orbitals. Each of the least squares fitted lines are presented along with the change rates.

Figure 5. Absolute values of the overlap integrals calculated for the valence MOs: overlap between (a) Ln orbital and ligand π orbital (metal-ligand overlap) and (b) two ligand π orbitals (ligand-ligand overlap).

Figure 6. MO energies with the SA-SCF method and fragment orbital energies calculated by the Fock matrix elements. The energies of each of the fragment orbitals (a) πe2u and (b) πe2g and (c) πe1u and (d) πe1g orbitals (represented by open marks and dotted lines) are compared with the MO energies (represented by solid marks and solid lines) with the respective symmetries. The energies of (e) a1g and a2u MOs are also shown for comparison. For the e2g, e1u and e1g MOs, the energies calculated using eqs 4 and 5 are also shown with open circles and crosses, respectively. The energies of (f) 5de2g and 5de1g and (g) 5pe1u atomic orbitals are also shown. Each of the least squares fitted lines are presented along with the rates of the energy change versus atomic number of Ln.

Figure 7. Relative energy level diagram of the anion (each left-hand panel) and neutral (right-hand panel) states of (a) Ce, (b) Nd, (c) Sm, and (d) Ho complexes calculated with the ∆MCQDPT2 37



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

method. The energies are given relative to the respective anion ground states specified with red color. The occupation number of 4fe2u orbitals in each of the dominant configurations is represented by the number of asterisks which are attached to the |ML| values as superscripts, for example, 0** means two 4fe2u electrons exist in the dominant configuration of the ML=0 state. The multihued neutral levels represent the mixing of several |ML| states, in which the relative length of each colored part represents the percentage of the corresponding |ML| state.

Figure 8. Configuration mixing and energy splitting pattern in the neutral states. By the configuration mixing with Ln4+ configuration, (a)(b) a part of the low-spin states with (4fe2u)1(πe2u)3 configuration are stabilized, (c)(d) all of the low-spin states with (4fe2u)2(πe2u)3 configuration are stabilized, and (e)(f)(g) both the low- and high-spin states with (4fe2u)3(πe2u)3 configuration are stabilized and their splitting pattern critically depends on the irreducible representation of the Γelse. When Γelse is (B1,B2), each degeneracy is resolved. Note these configurations schematically represent spin-adapted normalized Slater determinants, thus those in (a) (e) are singlet, those in (c) are doublet, and those in (f) are triplet in these e2u symmetry part.

Figure 9. VDEs of the X peaks calculated by (a) ∆SA-CASSCF and (b) ∆MCQDPT2 methods. The open circles and cross marks denote the VDEs leading to the low- and high-spin final states, respectively. The VDEs assigned by Koopmans’ theorem are also represented by the asterisks.

38


Page 38 of 48

R (Ln-COT) (Å)

2.339 Page TheofJournal 48 of Physical Chemistry

1 2 3 4 5 6 7 8 9 10

2.2 2.1

-0.0188 Å

2.0 1.9

1.8


La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ln3+ Ion

The Journal of Physical Chemistry Page 40 of 48 5d e 1 pe2u

e2u

2 3 pe2g e2g 4 e1u 5 pe1g 6 e1g 7pe1u 8 9 10 11 4f 12 13 14 5p 15 ACS Paragon Plus Environment 16 (COT)24- Gd(COT)2- Gd3+ 17 18

2u

e2g

e1u

e1g

Page 2.0 41 TheofJournal 48 of Physical Chemistry

VDE (eV)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

2.5

0.0267 eV

3.0

VDE(X): e2u VDE(X’): e2u

VDE(A): e2g

3.5

-0.008 eV 4.0

La Ce Pr NdPmSmEu Gd Tb Dy Ho Er TmYb Lu

Ln Environment Ion ACS Paragon Plus 3+

1.6

The Journal of Physical Chemistry Page 42 of 48

< r > (Å)

1.4 -0.0125 Å 1 2 1.2 3 5s 4 1.0 5p -0.0151 Å 5 5d 6 0.8 7 -0.0145 Å Plus Environment 8 ACS Paragon 9 0.6 La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu 10 Ln3+ Ion

0.30

1 2 0.25 3 4 0.20 5 6 0.15 7 8 0.10 9 10 0.05 11 12 0.00 13 14

The Journal of Physical 0.070 Chemistry

(a)

e2g (p -5d)

e1g (p -5d) e1u (p -5p)

e2u (p -4f) e1u (p -4f) a2u (p -4f)

Interligand Overlap Integral

Metal-Ligand Overlap Integral

Page 0.3543 of 48

0.065

(b)

e1u e2u

0.060 0.055 0.050 0.045

e2g

0.040

e1g

0.035 0.030

0.025

ACS Paragon Plus Environment 0.020

La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ln3+

Ion


Ln3+ Ion

Orbital Energy (eV)

Orbital Energy (eV)

0.0128 eV (pe2u)

0.0159 eV (e2u)

-3.0

-4.0

(c)

-0.0331 eV (e1u)

-0.0373 eV (eq 4)

(b)

-4.5

-0.0053 eV (eq 5) La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ln3+ Ion

-7.5 -8.0 -8.5 -9.0

(d)

0.0164 eV (pe1g)

0.0175 eV (e1g) 0.0172 eV (eq 4)

-9.5

0.0375 eV (eq 5)

-0.0245 eV (pe1u)

-10.0


Ln3+ Ion

(e)

Page 44 of 48

-0.0077 eV (eq 4)

Ln3+ Ion

-0.0638 eV (eq 5)

-0.0131 eV (pe2g)

-0.0095 eV (e2g)

-3.5

-5.0


Orbital Energy (eV)

Orbital Energy (eV)

1 2 -2.2 3 4 -2.3 5 6 -2.4 7 8 -2.5 9 10 11 -7.0 12 13 -7.5 14 15 -8.0 16 17 -8.5 18 19 -9.0 20 21 -9.5 22 23 24 -9.0 25 26 27 -9.5 28 29 -10.0 30 31 32 -10.5 33 34 -11.0 35 36 37 -20 38 39 -24 40 41 -28 42 43 -32 44 45 -36 46 47 -40 48 49

(a)

Orbital Energy (eV)

-2.1

-2.5 The Journal of Physical Chemistry


Ln3+ Ion 6.0

-0.0089 eV (a2u)

-0.0368 eV (a1g) La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu

(f) Orbital Energy (eV)

Orbital Energy (eV)

-2.0

4.0

0.0679 eV (5de2g)

2.0

0.0570 eV (5de1g)

0.0 -2.0


Ln3+ Ion

Ln3+ Ion

(g)

-0.823 eV (5pe1u) ACS Paragon Plus Environment La Ce Pr Nd PmSm Eu Gd Tb Dy Ho Er Tm Yb Lu

Ln3+ Ion

(a) Page 45 of 48

(b) Chemistry The Journal of Physical

0.5

1.8

|ML| 1.9

0.3

1.8

0.2

1.7

0.1

0.4

Relative Energy (eV)

0.4

|ML| 0 1 2* 3

0.5

0.8

0.3

0** 1* 2* 3 4* 5* 6*

1.7

1.6

E1 E3 E2

0.2

1.5

E1 A2

0.1

1.4

E2 E3

A1

0.0

doublet

Ce(COT)2-

0.7

singlet

0.0

triplet

Nd(COT)2-

Ce(COT)2

1.3

B1, B2

quartet

triplet

quintet

Nd(COT)2

(d) 0.5

1.8

0.5

|ML| 0.4

0.3

1.8

|ML|

0** 1* 2* 3** 4** 5*

E3 B1, B2 A2 E1 E3

1.7

1.6

E2 E2

0.2

E1

0.1

1.5

0.4




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 (c) 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

2.0

0.3

0**** 1*** 2*** 3** 4*** 5*** 6***

1.7

E2

E1

1.6

E3

E1

A2 0.2

E2

B1, B2

1.5

E3 1.4

0.1

1.4

1.3

0.0

1.3

A1 E3 0.0

sextet

Sm(COT)2-

quintet

ACS Paragon Plus Environment septet quintet

Sm(COT)2

Ho(COT)2-

quartet

sextet

Ho(COT)2

1 3 configuration neutral states withof (4fPhysical e2u) (pe2u)Chemistry The Journal

(a) 1 A : 1 2 3 4 A2 : 5 6 7 B1 : 8 9 10 11 (c) 12 13 14 E : 15 2 16 17 18 19 20 21 (e) 22 23A : 1 24 25 26B1 : 27 28 (f) 29 30A1 : 31 32 33A : 2 34 35 36 B1 : 37 38

pe2u

cos2f sin2f

Page 46 of 48

(b)

c Ln4+ configuration

4fe2u

low-spin

low-spin high-spin

B2 :

high-spin

Gelse :

E1, E2, E3, (B1,B2)

Gelse : (A1, A2)

neutral states with (4fe2u)2(pe2u)3 configuration

(d)

Gelse : (A1, A2)

Gelse : E1, E3, (B1,B2)

Gelse : E2

low-spin high-spin

low-spin high-spin

c c low-spin

high-spin

neutral states with (4fe2u)3(pe2u)3 configuration

A2 :

c c

c

B2 :

(g)

c low-spin

B2 :

low-spin


high-spin

Gelse : (A1, A2)

Gelse :

high-spin

E1, E2, E3, (B1,B2)

1.0

The Journal of Physical1.0 Chemistry

1 2 3 4 5 6 7 8 9 10

(a)

(b)

1.5

2.0

low-spin

Koopmans

high-spin

MCQDPT2 VDE (eV)

SA-CASSCF VDE (eV)

Page 47 of 48

low-spin

1.5

high-spin 2.0

Koopmans

ACS Paragon Plus Environment 2.5

2.5

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb

Ln3+ Ion

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb

Ln3+ Ion

interaction The Journal oforbital Physical Chemistry Page 48 of 48    COT S 2    COT

 Ln   COT

1 2 3 lanthanide contraction 4 pe2u 5 -2 ACS +3 -2 Paragon Plus Environment 4fe2u 6 7electrostatic effect configuration mixing

Theoretical Study on the Photoelectron Spectra of Ln(COT)2

Recommend Documents