1
|
Liu Z, Tang Y, Niu S, Shan X, Xu C, Chen X. Electron Momentum Spectroscopy Study on the Valence Electronic Structure of Dimethyl Sulfide Considering Vibrational Effects. J Phys Chem A 2020; 124:8551-8561. [PMID: 32966068 DOI: 10.1021/acs.jpca.0c07438] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report an electron momentum spectroscopy study on the valence electronic structure of dimethyl sulfide. The binding energy and electron momentum profiles are measured using a high-sensitivity (e, 2e) apparatus employing a symmetric non-coplanar geometry at an incident energy of 1200 eV plus binding energy. The measurements are compared with the theoretical calculations by density functional theory performed both at equilibrium molecular geometry and by considering vibrational effects through a harmonic analytical quantum mechanical approach. The results demonstrate a significant influence of nuclear vibrational motions on the momentum profiles for valence orbitals of dimethyl sulfide, especially for 5b2, 1a2, and 4b2. A detailed analysis shows that the observed vibrational effects come mainly from vibrational normal modes breaking the mirror symmetry of (CH3)2S with respect to a plane perpendicular to the O-S-O plane.
Collapse
Affiliation(s)
- ZhaoHui Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - YaGuo Tang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - ShanShan Niu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xu Shan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - ChunKai Xu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - XiangJun Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| |
Collapse
|
2
|
Tang Y, Shan X, Niu S, Liu Z, Wang E, Watanabe N, Yamazaki M, Takahashi M, Chen X. Electron Momentum Spectroscopy Investigation of Molecular Conformations of Ethanol Considering Vibrational Effects. J Phys Chem A 2017; 121:277-287. [PMID: 27998060 DOI: 10.1021/acs.jpca.6b10009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interpretation of experimental electron momentum distributions (EMDs) of ethanol, one of the simplest molecules having conformers, has confused researchers for years. High-level calculations of Dyson orbital EMDs by thermally averaging the gauche and trans conformers as well as molecular dynamical simulations failed to quantitatively reproduce the experiments for some of the outer valence orbitals. In this work, the valence shell electron binding energy spectrum and EMDs of ethanol are revisited by the high-sensitivity electron momentum spectrometer employing symmetric noncoplanar geometry at an incident energy of 1200 eV plus binding energy, together with a detailed analysis of the influence of vibrational motions on the EMDs for the two conformers employing a harmonic analytical quantum mechanical (HAQM) approach by taking into account all of the vibrational modes. The significant discrepancies between theories and experiments in previous works have now been interpreted quantitatively, indicating that the vibrational effect plays a significant role in reproducing the experimental results, not only through the low-frequency OH and CH3 torsion modes but also through other high-frequency ones. Rational explanation of experimental momentum profiles provides solid evidence that the trans conformer is slightly more stable than the gauche conformer, in accordance with thermodynamic predictions and other experiments. The case of ethanol demonstrates the significance of considering vibrational effects when performing a conformational study on flexible molecules using electron momentum spectroscopy.
Collapse
Affiliation(s)
- Yaguo Tang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xu Shan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Shanshan Niu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Zhaohui Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Enliang Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Masakazu Yamazaki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Xiangjun Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| |
Collapse
|
3
|
Li M, Shan X, Niu SS, Tang YG, Wu F, Xu CK, Chen XJ. High Resolution Electron Momentum Spectroscopy Study on Ethanol: Orbital Electron Momentum Distributions for Individual Conformers. CHINESE J CHEM PHYS 2016. [DOI: 10.1063/1674-0068/29/cjcp1604080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
4
|
Tang Y, Shan X, Yang J, Niu S, Zhang Z, Watanabe N, Yamazaki M, Takahashi M, Chen X. Vibrational Effects on Electron Momentum Distributions of Outer-Valence Orbitals of Oxetane. J Phys Chem A 2016; 120:6855-63. [PMID: 27494262 DOI: 10.1021/acs.jpca.6b06706] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vibrational effects on electron momentum distributions (EMDs) of outer-valence orbitals of oxetane are computed with a comprehensive consideration of all vibrational modes. It is found that vibrational motions influence EMDs of all outer-valence orbitals noticeably. The agreement between theoretical and experimental momentum profiles of the first five orbitals is greatly improved when including molecular vibrations in the calculation. In particular, the large turn-up at low momentum in the experimental momentum profile of the 3b1 orbital is well interpreted by vibrational effects, indicating that, besides the low-frequency ring-puckering mode, C-H stretching motion also plays a significant role in affecting EMDs of outer-valence orbitals of oxetane. The case of oxetane exhibits the significance of checking vibrational effects when performing electron momentum spectroscopy measurements.
Collapse
Affiliation(s)
- Yaguo Tang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xu Shan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Jing Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Shanshan Niu
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Zhe Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Masakazu Yamazaki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Sendai 980-8577, Japan
| | - Xiangjun Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| |
Collapse
|
5
|
Morini F, Watanabe N, Kojima M, Deleuze MS, Takahashi M. Electron momentum spectroscopy of dimethyl ether taking account of nuclear dynamics in the electronic ground state. J Chem Phys 2015; 143:134309. [PMID: 26450316 DOI: 10.1063/1.4931918] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b1, 6a1, 4b2, and 1a2 orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point out in particular the most appreciable role which is played by a few specific molecular vibrations of A1, B1, and B2 symmetries, which correspond to C-H stretching and H-C-H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing.
Collapse
Affiliation(s)
- Filippo Morini
- Center of Molecular and Materials Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
| | - Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Masataka Kojima
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Michael Simon Deleuze
- Center of Molecular and Materials Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| |
Collapse
|
6
|
Morini F, Deleuze MS, Watanabe N, Takahashi M. Theoretical study of molecular vibrations in electron momentum spectroscopy experiments on furan: an analytical versus a molecular dynamical approach. J Chem Phys 2015; 142:094308. [PMID: 25747082 DOI: 10.1063/1.4913642] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The influence of thermally induced nuclear dynamics (molecular vibrations) in the initial electronic ground state on the valence orbital momentum profiles of furan has been theoretically investigated using two different approaches. The first of these approaches employs the principles of Born-Oppenheimer molecular dynamics, whereas the so-called harmonic analytical quantum mechanical approach resorts to an analytical decomposition of contributions arising from quantized harmonic vibrational eigenstates. In spite of their intrinsic differences, the two approaches enable consistent insights into the electron momentum distributions inferred from new measurements employing electron momentum spectroscopy and an electron impact energy of 1.2 keV. Both approaches point out in particular an appreciable influence of a few specific molecular vibrations of A1 symmetry on the 9a1 momentum profile, which can be unravelled from considerations on the symmetry characteristics of orbitals and their energy spacing.
Collapse
Affiliation(s)
- Filippo Morini
- Center of Molecular and Materials Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
| | - Michael S Deleuze
- Center of Molecular and Materials Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek, Belgium
| | - Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| |
Collapse
|
7
|
Shi YF, Shan X, Wang EL, Yang HJ, Zhang W, Chen XJ. Electron Momentum Spectroscopy of Outer Valence Orbitals of 2-Fluoroethanol. CHINESE J CHEM PHYS 2015. [DOI: 10.1063/1674-0068/28/cjcp1410175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
8
|
Watanabe N, Yamazaki M, Takahashi M. Vibrational effects on valence electron momentum distributions of CH2F2. J Chem Phys 2014; 141:244314. [PMID: 25554158 DOI: 10.1063/1.4904705] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report an electron momentum spectroscopy study of vibrational effects on the electron momentum distributions for the outer valence orbitals of difluoromethane (CH2F2). The symmetric noncoplanar (e,2e) experiment has been performed at an incident electron energy of 1.2 keV. Furthermore, a theoretical calculation of the electron momentum distributions of the CH2F2 molecule has been carried out with vibrational effects being involved. It is shown from comparisons between experiment and theory that it is essential to take into account influences of the CH2 asymmetric stretching and CH2 rocking vibrational modes for a proper understanding of the electron momentum distribution of the 2b1 orbital having the CH-bonding character. The results of CH2F2and additional theoretical calculations for (CH3)2O and H2CO molecules strongly suggest that vibrational effects on electron momentum distributions tend to be appreciable for non-total symmetry molecular orbitals delocalized over some equivalent CH-bond sites.
Collapse
Affiliation(s)
- Noboru Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Masakazu Yamazaki
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Masahiko Takahashi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| |
Collapse
|
9
|
Shi Y, Shan X, Wang E, Yang H, Zhang W, Chen X. Experimental and Theoretical Investigation on the Outer Valence Electronic Structure of Cyclopropylamine by (e, 2e) Electron Momentum Spectroscopy. J Phys Chem A 2014; 118:4484-93. [DOI: 10.1021/jp503198r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Yufeng Shi
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xu Shan
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Enliang Wang
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hongjiang Yang
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei Zhang
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiangjun Chen
- Hefei National Laboratory
for Physical Sciences at the Microscale and Department of Modern Physics and Synergetic Innovation Center of Quantum Information
and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| |
Collapse
|