Evidence for Water Antibonding Orbital Mixing in the Hydrated Electron from Its Oxygen 1s X-ray Absorption Spectrum

Xingpin Li; Xiangyu Jia; Amiel S P Paz; Yuquan Cao; William J Glover

doi:10.1021/jacs.2c07572

Evidence for Water Antibonding Orbital Mixing in the Hydrated Electron from Its Oxygen 1s X-ray Absorption Spectrum

J Am Chem Soc. 2022 Nov 2;144(43):19668-19672. doi: 10.1021/jacs.2c07572. Epub 2022 Oct 17.

Authors

Xingpin Li^{1

2

3}, Xiangyu Jia^{1

2}, Amiel S P Paz^{1

2

3}, Yuquan Cao^{1

2

3}, William J Glover^{1

2

3}

Affiliations

¹ NYU Shanghai, 1555 Century Avenue, Shanghai, 200122, China.
² NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshang Road, Shanghai, 200062, China.
³ Department of Chemistry, New York University, New York, New York10003, United States.

PMID: 36251402
DOI: 10.1021/jacs.2c07572

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.