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Title: Quantum dynamical investigation of the simplest Criegee intermediate CH{sub 2}OO and its O–O photodissociation channels

The singlet electronic potential energy surfaces for the simplest Criegee intermediate CH{sub 2}OO are computed over a two-dimensional reduced subspace of coordinates, and utilized to simulate the photo-initiated dynamics on the S{sub 2} (B) state leading to dissociation on multiple coupled excited electronic states. The adiabatic electronic potentials are evaluated using dynamically weighted state-averaged complete active space self-consistent field theory. Quasi-diabatic states are constructed from the adiabatic states by maximizing the charge separation between the states. The dissociation dynamics are then simulated on the diabatically coupled excited electronic states. The B ← X electronic transition with large oscillator strength was used to initiate dynamics on the S{sub 2} (B) excited singlet state. Diabatic coupling of the B state with other dissociative singlet states results in about 5% of the population evolving to the lowest spin-allowed asymptote, generating H{sub 2}CO (X {sup 1}A{sub 1}) and O ({sup 1}D) fragments. The remaining ∼95% of the population remains on repulsive B state and dissociates to H{sub 2}CO (a {sup 3}A″) and O ({sup 3}P) products associated with a higher asymptotic limit. Due to the dissociative nature of the B state, the simulated electronic absorption spectrum is found to be broad and devoid of any vibrationalmore » structure.« less
Authors:
; ; ;  [1]
  1. Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States)
Publication Date:
OSTI Identifier:
22436551
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTRA; COUPLING; DISSOCIATION; PHOTOLYSIS; POTENTIAL ENERGY; SIMULATION; SPIN