Multilevel Redfield description of the dissipative dynamics at conical intersections

The effect of a dissipative environment on the ultrafast dynamics at a conical intersection was explored. A simple two-state three-mode model derived from ab initio calculations for the S₁(nπ*) and S₂(ππ) PE surfaces of pyrazine was adopted as representative model of a conical intersection. While the strongly nonseparable non-Born-Oppenheimer dynamics of the system was treated numerically exactly, the coupling with the bath was described within the Born and Markovian approximations. The resulting data was analyzed.