报告摘要

Conical intersections are multi-dimensional seams of exact degeneracies of Born-Oppenheimer potential-energy surfaces of polyatomic molecules. Conical intersections play a crucial role in photophysics, photochemistry and photobiology. At these multi-dimensional intersection seams, the molecular dynamics is dominated by a complete breakdown of the Born-Oppenheimer approximation as well as by exceptionally strong anharmonic couplings of vibrational modes. Starting from a historical overview of the Born-Oppenheimer approximation and the concept of conical intersections, this lecture traces the development of early as well as more recent methods which allow the computational study of the time-dependent nonadiabatic dynamics at conical intersections. A brief overview is also given of the development of theoretical concepts and computational techniques which allow the simulation of time and frequency resolved pump-probe spectra with quantum wave-packet or quasi-classical trajectory methods. It is shown that photochemical dynamics in polyatomic molecules can nowadays be scrutinized in unprecedented detail by the interplay of laser spectroscopy and computational chemistry.