TY  - JOUR
IS  - 36
EP  - 7557
SN  - 1089-5639
TI  - Modeling Photodissociation: Quantum Dynamics Simulations of Methanol
AV  - public
KW  - Science & Technology
KW  -  Physical Sciences
KW  -  Chemistry
KW  -  Physical
KW  -  Physics
KW  -  Atomic
KW  -  Molecular & Chemical
KW  -  Chemistry
KW  -  Physics
KW  -  NONADIABATIC DIRECT-DYNAMICS
KW  -  PHOTOCHEMISTRY
KW  -  SPECTROSCOPY
KW  -  PATHWAYS
KW  -  ENERGY
N1  - Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under 
CC-BY 4.0 .
N2  - A comprehensive computational study of the gas-phase photodissociation dynamics of methanol is presented. Using a multiconfigurational active space based method (RASSCF) to obtain multidimensional potential energy surfaces (PESs) on-the-fly, direct quantum dynamics simulations were run using the variational multi-configurational Gaussian method (DD-vMCG). Different initial excitation energies were simulated to investigate the dependence of the branching ratios on the electronic state being populated. A detailed mechanistic explanation is provided for the observed differences with respect to the excitation energy. Population of the lowest lying excited state of methanol leads to rapid hydroxyl hydrogen loss as the main dissociation channel. This is rationalized by the strongly dissociative nature of the PES cut along the O-H stretching coordinate, confirmed by the broad feature in the absorption spectrum. In contrast, more energetic excitations lead mainly to C-O bond breaking. Again, analysis of the diabatic surfaces offers a clear explanation in terms of the nature of the electronic states involved and the coupling between them. The type of calculations presented, as well as the subsequent analysis of the results, should be seen as a general workflow for the modeling of photochemical reactions.
ID  - discovery10198987
UR  - http://dx.doi.org/10.1021/acs.jpca.4c03612
Y1  - 2024/08/28/
PB  - AMER CHEMICAL SOC
A1  - Cigrang, Leon LE
A1  - Worth, Graham A
JF  - The Journal of Physical Chemistry A
VL  - 128
SP  - 7546
ER  -