Band Shape of Vibrational Sum Frequency Generation Spectra of

Subscriber access provided by ECU Libraries

Surfaces, Interfaces, and Catalysis; Physical Properties of Nanomaterials and Materials (2)

Nuclear Quantum Effect on the # Band Shape of Vibrational Sum Frequency Generation Spectra of Normal and Deuterated Water Surfaces Tatsuya Ishiyama, and Akihiro Morita J. Phys. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.jpclett.9b02069 • Publication Date (Web): 15 Aug 2019 Downloaded from pubs.acs.org on August 19, 2019

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 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 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.

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 19 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 Letters

Nuclear Quantum Effect on the χ(2) Band Shape of Vibrational Sum Frequency Generation Spectra of Normal and Deuterated Water Surfaces Tatsuya Ishiyama∗,† and Akihiro Morita‡ † Department of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan

‡ Department of Chemistry Graduate School of Science Tohoku University Sendai 980-8578, Japan

¶ Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Kyoto 615-8520, Japan

E-mail: [email protected]

1

ACS Paragon Plus Environment

The Journal of Physical Chemistry Letters 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 19

Abstract In the vibrational sum frequency generation (VSFG) spectrum of air/water interface, there is an open question whether the imaginary spectrum of nonlinear susceptibility Im[χ(2)] has a positive band in low-frequency tail of the OH stretching band. We previously elucidated by molecular dynamics (MD) analysis of the VSFG spectrum that the positive band could arise from particularly strong hydrogen-bonded water pairs at water surface. This mechanism should be emphasized in OD stretching than in OH, since OD forms stronger hydrogen bonds. Therefore, we calculated the Im[χ(2)] spectra of normal and deuterated water surfaces by MD simulation including nuclear quantum effect, and demonstrated that the low-frequency positive feature could arise in the tail of the OD stretching band. This positive feature is sensitive to oxygen-oxygen distance of hydrogen-bonding pairs at the surface and hence the temperature, and disappears with increasing temperature.

Graphical TOC Entry

Vapor Liquid

0 Donar Acceptor

OD 2000

2400

OH 2800

3200

3600

Frequency (cm-1 )

2


4000

Page 3 of 19 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 vibrational sum frequency generation (VSFG) spectroscopy is a powerful probe method of liquid surfaces with excellent interfacial selectivity and sensitivity.1 In particular, recent collaboration of phase-sensitive (PS)2 or heterodyne-detected (HD)3 measurement of VSFG spectra and molecular dynamics (MD) simulation revealed detailed structure of the water surface characterized by the extensive hydrogen bond network in a few monolayer region. 4 The SFG spectra are governed by the nonlinear susceptibility of the interfaces χ(2), and the imaginary spectrum Im[χ(2)] of liquid water surface shows a sharp positive band at 3700 cm−1 and a broad negative band at 3000-3600 cm−1. These spectral features were predicted by MD simulation5,6 prior to experiment, and subsequently confirmed by the PS and HD VSFG measurements.4,7 One of the remaining controversies is whether the third positive band is present or not in the Im[χ(2)] vibrational spectrum in the low-frequency tail of OH stretching band besides the two features mentioned above. The early MD calculations by Morita et al.

5,6,8

did not predict the positive feature in the low-frequency tail, whereas the first experimental report of PS VSFG by Shen et al. showed the positive band. 7 The subsequent PS and HD VSFG experiments also showed this positive feature. 9–12 In response to these experimental results, theoretical groups independently provided explanations for the positive feature in the low-frequency tail. Ishiyama and Morita argued that the positive feature arises from tightly hydrogen-bonded water dimers at the surface, 13,14 while Skinner et al. attributed the feature to upward oriented water with their explicit three-body (E3B) model. 15,16 However, Yamaguchi and Tahara subsequently negated the positive feature by their experiments, arguing that it is due to an artifact of experimental phase calibration. 17,18 In response to their observations, Tian and Shen confirmed that the positive feature is not readily discernible,19 though they reported the apparent positive feature in the low-frequency tail of OD stretching band of isotope substituted water surface. 20 It is an open question whether the positive feature is present, especially in the OD stretching band, as several experimental groups have not reached a full consensus about their experimental results. In the theoretical side, some of

3



Page 4 of 19

the subsequent studies tried to explain the positive band, 21,22 while others did not reproduce the positive feature with various models of MD simulation.23–27 In the present paper we argue from a theoretical viewpoint that the positive feature should be more pronounced in the OD band than in the OH band. As we mentioned, we have shown by MD simulation that the OH (OD) stretching in tightly hydrogen-bonded water pairs at the surface tends to induce a positive component of the transition dipole, which elucidates the positive Im[χ(2)] feature in the low-frequency tail region. The key mechanism is that the induced positive component arises in particularly strong hydrogen-bonding water pairs. As a consequence, one can argue that OD should show the positive feature more than OH, considering that OD tends to form stronger hydrogen bonds than OH due to the nuclear quantum effect. We discuss that this difference between OD and OH naturally manifests itself in the MD simulation considering the nuclear quantum effect in the following. The present simulation employed the centroid MD scheme. 28 128 HOD water molecules form a liquid slab in a rectangular simulation box of Lx × Ly × Lz = 15.0 ˚ A × 15.0 ˚ A × 100.0 ˚ A

with three-dimensional periodic boundary conditions. The force field for the centroid MD was q-SPC/Fw model29 with our modified intramolecular potential, using the number of beads Nbeads = 24 per atom. HOD was adopted to minimize the effect of intramolecular vibrational coupling on the χ(2) spectra. The statistical sampling of the MD simulation was taken at T = 300 K from 32 independent trajectories for 120 ps each, which amounts to 3.84 ns in total. We also carried out the corresponding classical MD simulation instead of centroid MD to examine the quantum effect on the calculated results. The force field of the classical simulation was SPC/Fw model30 and Nbeads = 1, with the other conditions being same as the quantum simulation. The χ(2)(ω) spectrum as a function of the infrared frequency ω is calculated by the following time correlation function formula,6,31 (2) χpqr (ω)

iω = kB T B

∫∞ 0 0

dt exp(iωt)⟨A pq (t)M r(0)⟩ + χ(2),nonres , pqr 4


(1)

Page 5 of 19 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


(2) where the suffixes p, q, r denote the space-fixed coordinates x ∼ z. We treat the χxxz element

in the following, which corresponds to the ssp polarization combination of SFG measurement. (2),nonres The first term of r. h. s. is the vibrationally resonant term, and the second one χpqr

is the nonresonant term. The latter is regarded as a real constant, and thus omitted in the imaginary spectrum of χ(2), Im[χ(2)(ω)]. kB and T are the Boltzmann constant and temperature. ⟨Apq (t)Mr(0)⟩ is the time correlation function between polarizability tensor

Apq and dipole vector Mr of the interface system. The instantaneous values of Apq and Mr are calculated using the charge response kernel (CRK) model developed by us in Ref.14 The CRK model is defined on the basis of ab initio molecular orbital or density functional

theory (DFT), and designed to reproduce instantaneous values of molecular polarizability and dipole by ab initio or DFT calculations. 32 The present calculation of Apq and Mr fully takes account of the polarization couplings among the water molecules.32 We also tried to estimate the band shape of Im[χ(2)] in an alternative way using velocityvelocity autocorrelation function, 26 Ivvaf(ω) =

∫

0 0

∞

dt cos(ωt)

⟨ ∑ i

OH r˙ OH (0) r˙ i (t) z,i

i

|r˙

· r˙

OH

OH i

(t)

⟩

(2)

,

(t)|i

where rOH(t) represents OH (or OD) vector of ith molecule at time t, rOH is its z component, i

z

and r˙ with a dot denotes time derivative of r. Equation 2 approximates the χ(2) spectrum based on the vibrational density of states, with neglecting the polarization coupling in Apq and Mr in eq. 1. Thus the difference in the band shape between eqs. 1 and 2 allows for evaluating the effect of polarization coupling, which is manifested in the local field effect or non-Condon effect, on the Im[χ(2)(ω)] spectrum. The details of MD conditions and χ(2) calculations are shown in the Supporting Information. The MD calculations were carried out using the path integral MD (PIMD) program code developed by Shiga,

33

while the

calculation of χ(2) with the CRK model was conducted by our in-house program. Figure 1 shows the interfacial structure of HOD water by classical (black) and quantum 5



(green) MD simulations. Panel (a) displays the number density (n) of the water oxygen as a function of the interfacial depth z. The density profiles of classical and quantum simulations are quite similar to each other, as the SPC/Fw and q-SPC/Fw models were parameterized to well reproduce experimental bulk density and enthalpy of vaporization etc. The oscillating behavior of the density profiles comes from the fact that the present system size in the tangential directions (Lx, Ly ) is somewhat small in comparison with usual classical MD simulations, and thus capillary wave is suppressed in the present system. In fact, ab initio MD simulation using the Willard and Chandler instantaneous surface 34 showed a similar oscillating density at the air/water interface.21 In Fig. 1 (b), orientational profiles of OH (OD) bonds are shown. The ordinate of the graph indicates n times cos θ, where n is the number density and θ is an angle between surface normal and OH(OD) bond, as shown in the inset of Fig. 1 (b). Both classical and quantum profiles of n · cos θ has a negative region in 4 ˚ A≲ z≲ 8˚ A and a positive region in 8 ˚ A ≲ z. The former is attributed to hydrogen-bonding OH(OD) toward the bulk liquid,

and the latter to the free (or dangling) OH(OD). In the classical MD simulation the OH and OD profiles are indistinguishable, while they are distinguishable in the quantum simulation because of the nuclear quantum effect of H and D. The red and blue dashed lines in Fig. 1 (b) show n · cos θ profiles of OH and OD, respectively, in the quantum simulation, where the sum of them recovers the total distribution (green line). The negative hydrogen-bonding region is slightly enhanced in the OD case, whereas the positive free bond region is suppressed in the OD case. This is because OD tends to form a strong hydrogen bond to water oxygen in comparison with OH.35 (2) Figure 2 (a) represents the Im[χxxz (ω)] spectrum of HOD water by the quantum MD

simulation, which shows both the OD (2000 ∼ 2800 cm−1) and OH (3000 ∼ 3800 cm−1) regions. We see the difference in the band shapes in the OD and OH regions; the positive

feature in the low-frequency tail appears in the OD region whereas it disappears in the OH region. This tendency is consistent to the recent experiment by Xu et al. 20 We note

6


Page 6 of 19

Page 7 of 19 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


(2) that previous explanations of the positive Im[χxxz (ω)] feature in terms of “upward oriented”

surface water15,21,22 may have difficulty to elucidate the isotope effect of H and D, since OD should take more downward orientation than OH at water surface, as Fig. 1 (b) demonstrates. To elucidate the difference in the OD and OH bands, we decompose the Im[χ(2) ] amxxz plitude by the OH(OD) vibrations of different orientations into upward (0◦ ≤ θ ≤ 60◦), lateral (60◦ < θ < 120◦), and downward (120◦ ≤ θ ≤ 180◦). The spectral decomposition into

different orientations was performed by the same manner with our previous study. 36 Panels

(2) (b) and (c) of Figure 2 show the results of decomposed Im[χxxz (ω)] spectrum in the OD and

OH regions, respectively. Note that the sum of the three decomposed lines (blue, red, and (2)

green lines) corresponds to the total Im[χxxz (ω)] spectrum (black line), which is same as the (2) line in Fig. 2 (a). The decomposition analysis reveals that the total Im[χxxz ] amplitude is

a consequence of cancellation of the upward and downward OH(OD) contributions (see the insets of (b) and (c)). More importantly, the lateral OH(OD) (red line) generates the positive (2) Im[χxxz (ω)] feature in the low-frequency region, and this positive feature is more pronounced

in the OD region than in the OH region. One can argue that the different band shapes in the low-frequency tail are attributed to the different contributions of lateral OH/OD vibrations. We also note in passing that the velocity-velocity correlation function Ivvaf(ω) of eq. (2) does not reproduce the positive feature in either OH or OD region (see the result in Supporting Information), demonstrating that this feature arises from the intermolecular polarization coupling. (2) In our previous study, 4,13,14,37,38 we discussed that the positive Im[χxxz (ω)] band in the

low-frequency region was reproduced in the classical MD simulation (see Fig. 4), and it was attributed to strongly hydrogen-bonded OH(OD) molecules at the surface, where the tangential OH vibration (red arrow in Fig. 2(d)) can induce a normal component of the transition dipole to the surface (blue arrow in Fig. 2(d)). We called this mechanism “anisotropic local field effect”, which is characteristic to strong hydrogen-bonded pairs in the anisotropic interface environment. This feature of strong hydrogen bond emerges in the very low-frequency

7



region of the OH vibration. In the present quantum MD simulation, essentially the same (2) mechanism should hold for the Im[χxxz (ω)] band, though the strength of hydrogen bonds

is affected by the quantum nature of H and D. Since the anisotropic local field effect is particularly pronounced in the strongly hydrogen-bonding complexes, the different nuclear quantum effects of H and D may result in the different amount of the positive feature in the low-frequency tail. The different nuclear quantum effects of H and D are manifested in the oxygen-oxygen distances of hydrogen-bonding pairs, ROO, in the present quantum MD simulation. Figure 3 summarizes the average ROO of O − H · · · O and O − D · · · O for different orientations and

depth regions. Here the H-bond is defined by the conditions that the H · · · O distance is less

than 2.5 ˚ A and the O − H · · · O angle is larger than 150◦. The three orientations (upward, lateral, downward) are defined by the OH(OD) angle in the same manner as in Fig. 2,

and the depth regions (I, II, III) are defined by 3.5 ˚ A spacing from the Gibbs dividing surface, as illustrated in Fig. 3. Panels (a)-(c) of Fig. 3 shows that ROO of hydrogen-bonded O − D · · · O (open circles) are systematically smaller than that of O − H · · · O (filled circles) over all orientations and depth regions, confirming that the stronger hydrogen bonds of OD

than OH are reproduced in the present MD simulation. Since the nuclear wavefunction of D is less delocalized than H, the average distance of O − D · · · O becomes shorter than that of

O−H · · · O. A shorter O-O distance produces a hydrogen-bonding complex, inducing a large dipole moment in z direction due to the anisotropic polarization coupling (see Fig. 2(d)). (2) This is the reason why OD stretching region has the positive response in Im[χxxz ] than OH

stretching region. By further investigating ROO in different orientations and depth regions by the present MD simulation, we find the following anisotropic features at the interfaces. Now we focus on ROO of Region II in Fig. 3, because density of Region I is relatively smaller than that of Region II at the interface [n(Region II)/n(Region I) ∼ 2], and the main contribution of water molecules to the VSFG spectrum in the lower frequency side of the hydrogen-bond

8


Page 8 of 19

Page 9 of 19 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


region may come from those in Region II. In Region II, ROO of the upward component (panel a in Fig. 3) is larger than that of the lateral (panel b) or downward (panel c) components. Thus, in the present quantum MD simulation, there is no strong hydrogen-bond structure for upward direction of OH(OD). The lateral bonding structure in Region II can be the (2) only source of the lower frequency positive feature observed in the Im[χxxz ] spectrum, as

schematically shown in Fig. 2(d). (2) Finally we discuss the Im[χxxz(ω)] spectrum calculated by classical MD simulation in

Fig. 4. The black line (at 300 K) apparently shows the positive feature in the low-frequency tail of OH as well as OD vibration. This result is in accord with our previous study, 4,13,14,37,38 and indicates that the classical simulation could yield the positive feature more readily than the quantum simulation. The present results allow us to conclude that the nuclear quantum effect tends to smear the positive feature, essentially because the delocalized nuclear wavefunction hampers rigid hydrogen bond formation. The quantum effect of OH is larger than OD, and thus smears the positive feature more in the OH region. In relation to this argument, we also examined the temperature dependence of the band shape. Figure 4 also (2) shows the Im[χxxz (ω)] spectrum calculated at a somewhat higher temperature T = 330 K.

The spectrum at the higher temperature produces less positive feature in the low-frequency tail regions of OH and OD vibrations, though the band shape of the other frequency regions of OH or OD is not sensitive to the temperature. This result of temperature dependence is also understood from the fact that the positive feature in the low-frequency tail is particularly sensitive to oxygen-oxygen distance of hydrogen-bonding pairs at the surface. This result (2)

implies that the positive Im[χ xxz(ω)] feature in the low-frequency tail should become more apparent with lowering temperature. (2) In summary, we demonstrate that the low-frequency tail region of Im[χxxz (ω)] spectrum

of water involves intriguing information on strong hydrogen-bonded complexes at the surface. The positive band in the tail region arises from the polarization coupling of strong hydrogenbonded pairs, and thus it may not be well reproduced by other models of χ(2) estimation 9



based on single molecular orientation or velocity-velocity correlation. The present study with quantum and classical MD simulations consistently elucidates those effects of the OH and OD isotopes as well as temperature on the band shape in the low-frequency tail region. Finally we make a comment on the possibility of experimental observation of the positive feature, since it is currently a matter of controversy. The experimental detection may be challenging, as we argued in Figure 2 that the positive feature of Im[χ(2) (ω)] in the low-frequency xxz region could interfere with large cancellation of upward and downward contributions. Nevertheless, the present study demonstrated that the positive feature is more pronounced in the OD stretching than OH, and/or with decreasing temperature. In addition to the isotope substitution, 20 low-temperature conditions are suitable to detect the positive feature. The (2) Im[χxxz ] spectrum observed by Smit et al. showed the weak but non-negligible positive band

at the temperatures near or below the melting point of water.12,39 The extensive temperature dependence of the band shape in combination of isotope substitution provides an interesting opportunity to explore the positive feature and the related mechanism.

Acknowledgement We are grateful to Dr. Tahei Tahara for his critical and constructive comments and to Dr. Motoyuki Shiga for supporting the use of the PIMD code. A part of MD calculations were performed using the supercomputers at Research Center for Computational Science, Okazaki, Japan. This work was supported by the Grants-in-Aid (Nos. 16H04095, 18H05265) by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

Supporting Information Available Supporting Information Available: Details of MD conditions, self and cross correlation parts (2) of Im[χxxz ] spectrum, band shape analysis of Im[χ xxz ] in different cases.

10


Page 10 of 19

Page 11 of 19 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


References (1) Shen, Y. R. Fundamentals of Sum-Frequency Spectroscopy ; Cambridge University Press, 2016. (2) Shen, Y. R. Phase-Sensitive Sum-Frequency Spectroscopy. Annu. Rev. Phys. Chem. 2013, 64, 129. (3) Nihonyanagi, S.; Mondal, J. A.; Yamaguchi, S.; Tahara, T. Structure and Dynamics of Interfacial Water studied by Heterodyne-Detected Vibrational Sum-Frequency Generation. Annu. Rev. Phys. Chem. 2013, 64, 579. (4) Nihonyanagi, S.; Ishiyama, T.; Lee, T.; Yamaguchi, S.; Bonn, M.; Morita, A.; Tahara, T. Unified Molecular View of Air/Water Interface Based on Experimental and Theoretical Chi Spectra of Isotopically Diluted Water Surface. J. Am. Chem. Soc. 2011, 133, 16875. (5) Morita, A.; Hynes, J. T. A Theoretical Analysis of The Sum Frequency Generation Spectrum of the Water Surface. Chem. Phys. 2000, 258, 371. (6) Morita, A.; Hynes, J. T. A Theoretical Analysis of the Sum Frequency Generation Spectrum of the Water Surface. II. Time-Dependent Approach. J. Phys. Chem. B 2002, 106, 673. (7) Ji, N.; Ostroverkhov, V.; Tian, C. S.; Shen, Y. R. New Information on Water Interfacial Structure Revealed by Phase-Sensitive Surface Spectroscopy. Phys. Rev. Lett. 2008, 100, 096102. (8) Morita, A. Improved computation of sum frequency generation spectrum of water surface. J. Phys. Chem. B 2006, 110, 3158. (9) Chen, X.; Hua, W.; Huang, Z.; Allen, H. C. Interfacial Water Structure Associated with Phospholipid Membranes Studied by Phase-Sensitive Vibrational Sum Frequency Generation Spectroscopy. J. Am. Chem. Soc. 2010, 132, 11336. 11



(10) C. -S. Hsieh,; Okuno, M.; Hunger, J.; E. H. G. Backus,; Nagata, Y.; Bonn, M. Aqueous Heterogeneity at the Air/Water Interface Revealed by 2D-HD-SFG Spectroscopy. Angew. Chem. Int. Ed. 2014, 53, 8146. (11) Hu, D.; Chou, K. Re-Evaluating the Surface Tension Analysis of PolyelectrolyteSurfactant Mixtures Using Phase-Sensitive Sum Frequency Generation Spectroscopy. J. Am. Chem. Soc. 2014, 136, 15114. (12) F, W. S.; Tang, F.; Nagata, Y.; Sanchez, M.; Hasegawa, T.; Backus, E.; Bonn, M.; Bakker, H. Observation and Identification of a New OH Stretch Vibrational Band at the Surface of Ice. J. Phys. Chem. Lett. 2017, 8, 3656. (13) Ishiyama, T.; Morita, A. Vibrational spectroscopic response of intermolecular orientational correlation at water surface. J. Phys. Chem. C 2009, 113, 16299. (14) Ishiyama, T.; Morita, A. Analysis of Anisotropic Local Field in Sum Frequency Generation Spectroscopy with the Charge Response Kernel Water Model. J. Chem. Phys 2009, 131, 244714. (15) Pieniazek, P.; Tainter, C.; Skinner, J. Surface of liquid water: three-body ineractions and vibrational sum-frequency spectroscopy. J. Am. Chem. Soc. 2011, 133, 10360. (16) Pieniazek, P.; Tainter, C.; Skinner, J. Interpretation of the water surface vibrational sum-frequency spectrum. J. Chem. Phys. 2011, 135, 044701. (17) Yamaguchi, S. Development of single-channel heterodyne-detected sum frequency generation spectroscopy and its application to the water/vapor interface. J. Chem. Phys. 2015, 143, 034202. (18) Nihonyanagi, S.; Kusaka, R.; Inoue, K.; Adhikari, A.; Yamaguchi, S.; Tahara, T. Accurate determination of complex χ(2)spectrum of the air/water interface. J. Chem. Phys. 2015, 143, 124707. 12


Page 12 of 19

Page 13 of 19 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


(19) Sun, S.; Liang, R.; Xu, X.; Zhu, H.; Shen, Y.; Tian, C. Phase reference in phase-sensitive sum-frequency vibrational spectroscopy. J. Chem. Phys. 2016, 144, 244711. (20) Xu, X.; Shen, Y.; Tian, C. Phase-sensitive sum frequency vibrational spectroscopic study of air/water interfaces: H2O, D2O, and diluted isotopic mixtures. J. Chem. Phys. 2019, 150, 144701. (21) Pezzotti, S.; Galimberti, D.; Gaigeot, M. 2D H-Bond Network as the Topmost Skin to the Air-Water Interface. J. Phys. Chem. Lett. 2017, 8, 3133. (22) Liang, C.; Jeon, J.; Cho, M. Ab initio Modeling of the Vibrational Sum-Frequency Generation Spectrum of Interfacial Water. J. Phys. Chem. Lett. 2019, 10, 1153. (23) Medders, G.; Paesani, F. Dissecting the Molecular Structure of the Air/Water Interface from Quantum Simulations of the Sum-Frequency Generation Spectrum. J. Am. Chem. Soc. 2016, 138, 3912. (24) Kaliannan, N.; Aristizabal, A.; Wiebeler, H.; Zysk, F.; Ohto, T.; Na- gata,

Y.;

Ku ¨ hne, T. Impact of intermolecular vibrational coupling effects on the sumfrequency generation spectra of the water/air interface. Mol. Phys. 2019, https://doi.org/10.1080/00268976.2019.1620358. (25) Ni, Y.; Skinner, J. Vibrational sum-frequency spectrum of the air-water interface. J. Chem. Phys. 2016, 145, 031103. (26) Ohto, T.; Usui, K.; Hasegawa, T.; Bonn, M.; Nagata, Y. Toward ab initio molecular dynamics modeling for sum-frequency generation spectra; an efficient algorithm based on surface-specific velocity-velocity correlat function. J. Chem. Phys. 2015, 143, 124702. (27) Khatib, R.; Sulpizi, M. Sum Frequency Generation Spectra from Velocity.Velocity Correlation Functions. J. Phys. Chem. Lett. 2017, 8, 1310.

13



Page 14 of 19

(28) Lobaugh, J.; Voth, G. A. A quantum model for water: Equilibrium and dynamical properties. J. Chem. Phys. 1997, 106, 2400. (29) Paesani, F.; Zhang, W.; Case, D.; Cheatham III, T.; Voth, G. An accurate and simple quantum model for liquid water. J. Chem. Phys. 2006, 125, 184507. (30) Wu, Y.; Tepper, H.; Voth, G. Flexible simple point-charge water model with improved liquid-state. J. Chem. Phys 2006, 124, 024503. (31) Morita, A.; Ishiyama, T. Recent Progress in Theoretical Analysis of Vibrational Sum Frequency Generation Spectroscopy. Phys. Chem. Chem. Phys 2008, 10, 5801. (32) Morita, A. Theory of Sum Frequency Generation Spectroscopy ; Springer Nature Singapore Pte Ltd, 2018. (33) Shiga, M. PIMD program, version 2.2 (http://ccse.jaea.go.jp/ja/download/pimd/index.en.html). (34) Willard, A.; Chandler, D. Instantaneous Liquid Interfaces. J. Phys. Chem. B 2010, 114, 1954. (35) Nagata, Y.; Pool, R.; E. H. G. Backus,; Bonn, M. Nuclear Quantum Effects Affect Bond Orientation ofWater at theWater-Vapor Interface. Phys. Rev. Lett 2012, 109, 226101. (36) Ishiyama, T.; Terada, D.; Morita, A. Hydrogen-Bonding Structure at Zwitterionic Lipid/Water Interface. J. Phys. Chem. Lett. 2016, 7, 216. (37) Ishiyama, T.; Takahashi, H.; Morita, A. Vibrational Spectrum at a Water Surface: a Hybrid Quantum Mechanics/Molecular Mechanics Molecular Dynamics Approach. J. Phys. Condens. Matter 2012, 24, 124107. (38) Ishiyama, T.; Takahashi, H.; Morita, A. Molecular Dynamics Simulations of SurfaceSpecific Bonding of the Hydrogen Network of Water: A Solution to the Low SumFrequency Spectra. Phys. Rev. B 2012, 86, 035408. 14


Page 15 of 19 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


(39) F, W. S.; Bakker, H. The surface of ice is like supercooled liquid water. Angew. Chem. Int. Ed. 2017, 129, 15746.

15


60

Page 16 of 19

Classical MD Quantum MD

40 20

(a) 0 0

5

10

15

2

(mol/L)

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

Number density (mol/L)


(b) 0

-2

Classical MD Quantum MD OH OD

-4 0

5

10

15

Figure 1: (a) Number density n profiles of the water oxygen in the classical (black) and quantum (green) MD simulations as a function of the normal coordinate z. The origin of z corresponds to the center of mass of the water slab. (b) n times cos θ profiles of water, where θ is the tilt angle of OH (OD) from the surface normal, in the the classical (black) and quantum (green) MD simulations. The red and blue dashed lines represent n· cos θ of OH and OD, respectively, in the quantum MD simulation, and the sum of them corresponds to the green line.

16


Page 17 of 19 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

Vapor Liquid Liquid

0 Donar Donar Accepptor

-1 2000

(d)

(a) Quantum MD, 2400

2800

3200

3600

4000

-1

Frequency (cm ) Total

Upward

Lateral

Downward

1

1

(c) OH

(b) OD

0

0 5

5

0

0

-5 2000

-1 2 000

2400

-5 2400

3200

2800

2800

-1

3200

3600

3600

4000

4000

Figure 2: (a) Calculated Im[χ(2) xxz(ω)] spectrum of HOD water by quantum MD simulation. The panels (b) and (c) show the decomposed amplitudes in OD and OH regions, respectively, into three OH(OD) orientations; upward (0≤◦ θ ≤60◦, blue), lateral (60◦ < θ < 120◦, red) and downward (120◦ < θ ≤ 180◦, green). The whole amplitudes of the three orientations are displayed in the insets of (b) and (c). (d) Schematic of the polarization coupling (anisotropic local field) effect.

17



z^

Page 18 of 19

Gibbs dividing surface

0

8

Upward Region I

60°

Lateral Downward

120°

-3.5 Region II

(a) Upward Region I

OH OD

Region II Region III 2.78

2.79

2.8

2.81

2.79

2.8

2.81

2.79

2.8

2.81

(b) Lateral Region I Region II Region III 2.78

(c) Downward Region I Region II Region III 2.78

Figure 3: (Top panel) schematic picture of hydrogen-bonded water at surface, illustrating different orientations (upward, lateral, downward) and the depth region (I, II, ...). (a-c) average O − O distance ROO of hydrogen bond pairs for different orientations and depths. ROO in O −H O· · bond is represented in filled circle, while ROO in O− D · · ·O bond is · represented in open circle.

1


Page 19 of 19 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


300K 330K

1

0

-1 2000

Classical MD, 2400

2800

3200

3600

4000

-1

Frequency (cm ) Figure 4: Calculated Im[χ(2) xxz(ω)] spectra of HOD water by the classical MD simulation at T = 300 K (black solid) and 330 K (red dashed).

20


Band Shape of Vibrational Sum Frequency Generation Spectra of

Recommend Documents