Jakučionis Mantas, Mancal Tomas, Abramavičius Darius
Institute of Chemical Physics, Vilnius University, Sauletekio Ave. 9-III, LT-10222 Vilnius, Lithuania.
Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic.
Phys Chem Chem Phys. 2020 Apr 29;22(16):8952-8962. doi: 10.1039/d0cp01092h.
Effects of non-linear coupling between the system and the bath vibrational modes on the system internal conversion dynamics are investigated using the Dirac-Frenkel variational approach with a newly defined sD2 ansatz. It explicitly accounts for the entangled system electron-vibrational states, while the bath quantum harmonic oscillator states are expanded in a superposition of quantum coherent states. Using a non-adiabatically coupled three-level model, we show that efficient irreversible internal conversion due to quadratic vibrational-bath coupling occurs when the initially populated system vibrational levels are in resonance with the vibrational levels of a lower energy electronic state, also, a non-Gaussian bath wavepacket representation is required. The quadratic system-bath couplings result in broadened and asymmetrically squeezed bath quantum harmonic oscillator wavepackets in the coordinate-momentum phase space.
采用新定义的sD2近似的狄拉克-弗伦克尔变分方法，研究了系统与浴振动模式之间的非线性耦合对系统内转换动力学的影响。它明确考虑了纠缠的系统电子-振动状态，而浴量子谐振子状态则在量子相干态的叠加中展开。使用非绝热耦合三能级模型，我们表明，当初始填充的系统振动能级与较低能量电子态的振动能级共振时，由于二次振动-浴耦合会发生有效的不可逆内转换，此外，还需要非高斯浴波包表示。二次系统-浴耦合导致在坐标-动量相空间中浴量子谐振子波包变宽和不对称压缩。
