화학공학소재연구정보센터
Chemical Physics Letters, Vol.661, 83-88, 2016
Roaming mediated nonadiabatic dynamics in molecular hydrogen elimination from propane at 157 nm
The photofragmentation dynamics study using Tully's fewest switches trajectory surface hopping calculations, based on MRCIS(6,6)/6-31++G** potential energy surfaces, energy gradients and nonadiabatic couplings, reveals the occurrence of roaming mediated nonadiabatic pathways for the elimination of molecular hydrogen from propane at 157 nm. 1,2- and 1,3-molecular hydrogen eliminations, the minor dissociation channels, exclusively follow roaming (of partially dissociated H atom) mediated nonadiabatic pathway (S-1 -> S-0) to the ground electronic state followed by an atomic hydrogen abstraction from another carbon atom in the ground singlet (S-0) state. 1,1- and 2,2-molecular hydrogen eliminations on the other hand, the major dissociation processes, proceed either adiabatically in the first excited singlet (S-1) electronic state or through the internal conversion S-1 -> S-0 followed by direct two-body fragmentation in the ground singlet (S-0) state, with equal probability. (C) 2016 Elsevier B.V. All rights reserved.