Simulation of the photodeactivation of formamide in the nO-pi* and pi-pi* states: an ab initio on-the-fly surface-hopping dynamics study.
The short-time photodynamics (1 ps) of formamide in its low-lying singlet excited n(O)-pi(*) and pi-pi(*) states have been investigated by the direct trajectory surface-hopping method based on multiconfigurational ab initio calculations. The simulations showed that in both states, the primary deactivation process is C-N bond dissociation. In the ground state, the energy is transferred to (a) translational motion of the HCO and NH(2) fragments, (b) additional C-H dissociation from the vibrationally hot HCO fragment, or (c) formation of NH(3) and CO. In addition to the C-N dissociation pathway, C-O bond fission is found to be an additional primary deactivation path in the pi-pi(*) dynamics. From fractional occupations of trajectories, lifetimes of formamide were estimated: tau(S(1))=441 fs and tau(S(2))=66 fs.
D003198:Computer Simulation; D005559:Formamides / Q000737:chemistry*; D008956:Models, Chemical; D010777:Photochemistry; D011789:Quantum Theory; D013499:Surface Properties; D013997:Time Factors
D005559:Formamides; C031066:formamide