Ultrafast Dynamics of UV-Excited Imidazole

作者：Crespo Otero Rachel^*; Barbatti Mario; Yu Hui; Evans Nicholas L; Ullrich Susanne

来源：ChemPhysChem, 2011, 12(17): 3365-3375.

DOI：10.1002/cphc.201100453

• femtochemistry
• imidazole
• molecular dynamics
• photochemistry
• photoelectron spectroscopy

The ultrafast dynamics of UV-excited imidazole in the gas phase is investigated by theoretical nonadiabatic dynamics simulations and experimental time-resolved photoelectron spectroscopy. The results show that different electronic excited-state relaxation mechanisms occur, depending on the pump wavelength. When imidazole is excited at 239.6 nm, deactivation through the NH-dissociation conical intersection is observed on the sub-50 fs timescale. After 200.8 nm excitation, competition between NH-dissociation and NH-puckering conical intersections is observed. The NH-dissociation to NH-puckering branching ratio is predicted to be 21:4, and the total relaxation time is elongated by a factor of eight. A procedure for simulation of photoelectron spectra based on dynamics results is developed and employed to assign different features in the experimental spectra.

• 出版日期2011-12-9