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Li X, Jia X, Paz ASP, Cao Y, Glover WJ. Evidence for Water Antibonding Orbital Mixing in the Hydrated Electron from Its Oxygen 1s X-ray Absorption Spectrum. J Am Chem Soc 2022; 144:19668-19672. [PMID: 36251402 DOI: 10.1021/jacs.2c07572] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The X-ray absorption spectrum (XAS) of the hydrated electron (e(aq)-) has been simulated using time-dependent density functional theory with a quantum mechanics/molecular mechanics description. A unique XAS peak at 533 eV is observed with an energy and intensity in quantitative agreement with recent time-resolved experiments, allowing its assignment as arising from water O1s transitions to the singly occupied molecular orbital (SOMO) in which the excess electron resides. The transitions acquire oscillator strength due to the SOMO comprising an admixture of a cavity-localized orbital and water 4a1 and 2b2 antibonding orbitals. The mixing of antibonding orbitals has implications for the strength of couplings between e(aq)- and intramolecular modes of water.
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Affiliation(s)
- Xingpin Li
- NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China.,Department of Chemistry, New York University, New York, New York10003, United States
| | - Xiangyu Jia
- NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China
| | - Amiel S P Paz
- NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China.,Department of Chemistry, New York University, New York, New York10003, United States
| | - Yuquan Cao
- NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China.,Department of Chemistry, New York University, New York, New York10003, United States
| | - William J Glover
- NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China.,Department of Chemistry, New York University, New York, New York10003, United States
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Shen Z, Peng S, Glover WJ. Flexible boundary layer using exchange for embedding theories. II. QM/MM dynamics of the hydrated electron. J Chem Phys 2021; 155:224113. [PMID: 34911320 DOI: 10.1063/5.0067861] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The FlexiBLE embedding method introduced in Paper I [Z. Shen and W. J. Glover, J. Chem. Phys. 155, 224112 (2021)] is applied to explore the structure and dynamics of the aqueous solvated electron at an all-electron density functional theory Quantum Mechanics/Molecular Mechanics level. Compared to a one-electron mixed quantum/classical description, we find the dynamics of the many-electron model of the hydrated electron exhibits enhanced coupling to water OH stretch modes. Natural bond orbital analysis reveals this coupling is due to significant population of water OH σ* orbitals, reaching 20%. Based on this, we develop a minimal frontier orbital picture of the hydrated electron involving a cavity orbital and important coupling to 4-5 coordinating OH σ* orbitals. Implications for the interpretation of the spectroscopy of this interesting species are discussed.
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Affiliation(s)
- Zhuofan Shen
- NYU Shanghai, 1555 Century Ave., Shanghai 200122, China
| | - Shaoting Peng
- NYU Shanghai, 1555 Century Ave., Shanghai 200122, China
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