Full-dimensional adiabatic potential en-ergy surfaces of the electronic ground state X and nine excited states ?,(I-),(B-),(C-),(D-),(D-)',(D-)",(E-)'and(F-)of H2O molecule are developed at the level of internally con-tracted multireference configuration inter-action with the Davidson correction.The potential energy surfaces are fitted by us-ing Gaussian process regression combining permutation invariant polynomials.With a large selected active space and extra dif-fuse basis set to describe these Rydberg states,the calculated vertical excited en-ergies and equilibrium geometries are in good agreement with the previous theoretical and experimental values.Compared with the well-investigated photodissociation of the first three low-lying states,both theoretical and experimental studies on higher states are still limited.In this work,we focus on all the three channels of the highly excited state,which are directly involved in the vacuum ultraviolet photodissociation of water.In particular,some conical intersections of(D-)-(E-)',(E-)'-(F-),?-(I-)and(I-)-(C-)states are clearly illustrated for the first time based on the newly developed potential energy surfaces(PESs).The nonadiabatic dissociation pathways for these excited states are discussed in detail,which may shed light on the photodissociation mechanisms for these highly excited states.

Feng An;Shanyu Han;Xixi Hu;Kaijun Yuan;Daiqian Xie

Institute of Theoretical and Computational Chemistry,Key Laboratory of Mesoscopic Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210023,China;Department of Chemistry and Chemical Biology,University of New Mexico,New Mexico 87131,USA;Kuang Yarning Honors School,Institute for Brain Sciences,Nanjing University,Nanjing 210023,China;State key Laboratory of Molecular Reaction Dynamics,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China

化学物理学报（英文版）

[1]Feng An;Shanyu Han;Xixi Hu;Kaijun Yuan;Daiqian Xie-.Adiabatic Potential Energy Surfaces and Photodissociation Mechanisms for Highly Excited States of H2O)[J].化学物理学报（英文版）,2022(01):104-116

Photodissociation,multireference,ergies,photodissociation,PESs

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