We present a novel mixed quantum classical dynamical method to include solvent effects on internal conversion (IC) processes. All the solute degrees of freedom are represented by a wavepacket moving according to nonadiabatic quantum dynamics, while the motion of an explicit solvent model is described by an ensemble of classical trajectories. The mutual coupling of the solute and solvent dynamics is included within a mean-field framework and the quantum and classical equations of motions are solved simultaneously. As a test case we apply our method to the ultrafast ππ* → nπ* decay of thymine in water. Solvent dynamical response modifies IC yield already on the 50 fs time scale. This effect is due to water librational motions that stabilize the most populated state. Pure static disorder, that is, the existence of different solvent configurations when photoexcitation takes place, also has a remarkable impact on the dynamics.

中文翻译：

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显式溶剂模型中非绝热量子动力学的混合量子/经典方法：胸腺嘧啶在水中的ππ * /nπ*衰变作为测试案例

我们提出一种新颖的混合量子古典动力学方法，以包括内部转化（IC）过程的溶剂效应。所有溶质自由度都由根据非绝热量子动力学运动的波包表示，而显式溶剂模型的运动由一组经典轨迹描述。溶质动力学和溶剂动力学的相互耦合被包括在一个平均场框架内，并且同时解决了运动的量子方程和经典方程。作为测试案例，我们将我们的方法应用于超快ππ*→nπ*胸腺嘧啶在水中的衰减。溶剂动态响应已经在50 fs的时间范围内修改了IC产量。这种影响是由于水的自由运动稳定了人口最多的状态。纯静态无序，即光激发时不同溶剂构型的存在，对动力学也有显着影响。