Dynamics at conical intersections: The influence of O–H stretching vibrations on the photodissociation of phenol

Abstract

Comparing the recoil energy distributions of the fragments from one-photon dissociation of phenol-d(5) with those from vibrationally mediated photodissociation shows that initial vibrational excitation strongly influences the disposal of energy into relative translation. The measurements use velocity map ion imaging to detect the H-atom fragments and determine the distribution of recoil energies. Dissociation of phenol-d(5) molecules with an initially excited O-H stretching vibration produces significantly more fragments with low recoil energies than does one-photon dissociation at the same total energy. The difference appears to come from the increased probability of adiabatic dissociation in which a vibrationally excited molecule passes around the conical intersection between the dissociative state and the ground state to produce electronically excited phenoxyl-d(5) radicals. The additional energy deposited in electronic excitation of the radical reduces the energy available for relative translation.

Exploring the Time Scales of H-Atom Elimination from Photoexcited Indole

“…Currently, studies are underway in our group investigating the effects of vibrationally mediated photodissociation of the parent molecule in an attempt to understand the role of the excited electronic states of the partner fragments (minus H), as shown recently by Crim and co-workers. 25 …”

Conical intersection seam and bound resonances embedded in continuum observed in the photodissociation of thioanisole-d3

“…This determination, however, can allow for a powerful shortcut in understanding nonadiabatic chemical reactions wherein the full knowledge and elucidation of the whole complex multi-dimensional potential energy surfaces are not required. The structure and dynamic role of the conical intersection have been subjected to intensive theoretical [2][3][4][5][6][7][8][9] and experimental studies [10][11][12][13][14][15][16][17][18][19][20][21][22][23] for decades. Despite numerous successful theoretical and experimental studies, however, chemists still keenly undertake probing of the conical intersection region more directly.…”

Exploring Autoionization and Photoinduced Proton-Coupled Electron Transfer Pathways of Phenol in Aqueous Solution

“…1(b)) thus points in favor of an autoionization mechanism, followed by rapid deprotonation. [34][35][36][37][38][39] The solvent dependent photochemistry of phenol, is likely dictated by the magnitude of the hydration contribution to the thermodynamics of the charged reaction species.…”