title: Dynamic role of the intramolecular hydrogen bonding in nonadiabatic chemistry revealed in the UV photodissociation reactions of 2-fluorothiophenol and 2-chlorothiophenol.
abstract: The dynamic interplay between the intramolecular hydrogen bonding and intramolecular vibrational redistribution is found to be critical in nonadiabatic reaction dynamics. Herein, it has been demonstrated that the molecular planarity, directed by the intramolecular hydrogen bonding, plays an important role in the nonadiabatic passage of the reactive flux at the conical intersection in the photodissociation reactions of 2-fluorothiophenol and 2-chlorothiophenol. As the internal energy increases in the excited state, the intramolecular hydrogen bonding of 2-fluorothiophenol loosens. The floppiness brought into the molecular structure then modifies the dynamic path of the reactive flux, leading to the diminishment of the nonadiabatic transition probability at the conical intersection. On the contrary, for 2-chlorothiophenol having the relatively stronger intramolecular hydrogen bonding, the reactive flux seems to retain the molecular planarity even with the increase of the internal energy as manifested by the constant nonadiabatic transition probability over the wide range of the S1 internal energy. The effect of the intramolecular hydrogen bonding on the molecular structure and its relation to the nonadiabatic dynamics along the tunneling path has been experimentally demonstrated.
authors.affiliation: Department of Chemistry, KAIST , Daejeon 305-701, Republic of Korea.
authors.forename: Songhee
authors.initials: S
authors.lastname: Han
authors.forename: Hyun Sik
authors.initials: HS
authors.lastname: You
authors.forename: So-Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Sang Kyu
authors.initials: SK
authors.lastname: Kim
mesh_terms: D003198:Computer Simulation; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D055668:Photochemical Processes; D014466:Ultraviolet Rays; D014732:Vibration
chemical_list: D010636:Phenols