We theoretically investigate internal conversion processes of a photoexcited molecule in a condensed phase. The molecular system is described by two-dimensional adiabatic ground and excited potential energy surfaces that are coupled to heat baths. We quantify the role of conical intersection (CI) and avoided crossing (AC) in the PESs in dissipative environments by simulating the time evolution of wavepackets to compute the lifetime of the excited wavepacket, yield of the product, and adiabatic electronic coherence. For this purpose, we employ the multi-state quantum Fokker-Planck equation (MSQFPE) for a two-dimensional Wigner space utilizing the Wigner–Moyal expansion for the potential term and the Brinkman hierarchy expression for the momentum. We find that the calculated results are significantly different between the CI and AC cases due to the transition in the tuning mode and vibrational motion in the coupling mode.

我们理论上研究凝聚相中光激发分子的内部转化过程。分子系统由二维绝热基底和耦合到热浴的激发势能表面描述。我们通过模拟波包的时间演变以计算激发波包的寿命，产品的产率和绝热电子相干性，来量化在耗散环境中的PES中圆锥形交叉点（CI）和避免交叉点（AC）的作用。为此，我们采用了多态量子Fokker-Planck方程（MSQFPE）用于二维Wigner空间，利用Wigner-Moyal展开表示势项，并使用Brinkman层次表示表示动量。我们发现，由于调谐模式下的过渡和耦合模式下的振动运动，CI和AC情况之间的计算结果显着不同。