Borgis Daniel, Rossky Peter J, Turi László
Département Physique et Modélisation, Université d'Evry-Val-d'Essone, Boulevard François Mitterand, 91025 Evry, France.
J Chem Phys. 2006 Aug 14;125(6):64501. doi: 10.1063/1.2221685.
A new, alternative form of the golden rule formula defining the nonadiabatic transition rate between two quantum states in condensed phase is presented. The formula involves the quantum time correlation function of the energy gap, of the nonadiabatic coupling, and their cross terms. Those quantities can be inferred from their classical counterparts, determined via molecular dynamics simulations. The formalism is applied to the problem of the nonadiabatic p-->s relaxation of an equilibrated p-electron in water and methanol. We find that, in both solvents, the relaxation is induced by the coupling to the vibrational modes and the quantum effects modify the rate by a factor of 2-10 depending on the quantization procedure applied. The resulting p-state lifetime for a hypothetical equilibrium excited state appears extremely short, in the sub-100 fs regime. Although this result is in contrast with all previous theoretical predictions, we also illustrate that the lifetimes computed here are very sensitive to the simulated electronic quantum gap and to the strongly correlated nonadiabatic coupling.
本文提出了一种新的、定义凝聚相中两个量子态之间非绝热跃迁速率的黄金规则公式的替代形式。该公式涉及能隙、非绝热耦合及其交叉项的量子时间关联函数。这些量可以从通过分子动力学模拟确定的经典对应物中推断出来。该形式体系被应用于水中和甲醇中平衡态p电子的非绝热p→s弛豫问题。我们发现，在两种溶剂中，弛豫都是由与振动模式的耦合引起的，并且量子效应根据所应用的量子化程序将速率改变2到10倍。对于假设的平衡激发态，由此产生的p态寿命极短，处于亚100飞秒范围。尽管这一结果与之前所有的理论预测相反，但我们也表明，这里计算出的寿命对模拟的电子量子能隙和强相关的非绝热耦合非常敏感。
