H++CO2散射在30电子伏能量下电荷转移和非电荷转移的非绝热分子动力学模拟

在大气化学、天体物理学和癌症质子疗法中都涉及到高能H⁺+CO₂散射反应.本文在最简电子-核动力学（SLEND）基础上系统研究在30 eV下的H⁺+CO₂散射.SLEND用经典力学描述核，用单行列式Thouless波函数描述电子.本文模拟了CO₂在42个取向共3402条轨线，为理解H⁺+CO₂散射中的各个反应过程和机制提供了系统描述：非电荷转移散射（NCTS），电荷转移散射（CTS）和C=O双键的断裂，这些关于反应的有用信息不能完全从实验中获取.本文提供了散射的详尽细节，包括随CO₂取向不同主彩虹角和次彩虹角的出现和合并.SLEND NCTS和CTS的微分散射截面通过高等半经典方法计算，显示NCTS散射截面对所有散射角都同实验符合得很好，而CTS散射截面只大散射角时同实验结果符合得很好而在小角散射时稍差.无论是CTS还是NCTS SLEND都预言了主彩虹角的特征，这同实验完全一致.     

二能级体系的动态局域化

综述了我们在二能级体系的动态局域化方面所作的工作.通过把受驱二能级体系的量子动力学映射到在二维谐性势场和与之垂直的周期性磁场中粒子的经典动力学,使得对局域化机制理解更为深刻.应用这种方案就可以得到在线性偏振场作用下二能级体系的局域化条件.同时解析地分析了在脉冲场和圆偏振场驱动下二能级体系的局域化,发现圆偏振场诱导的局域化可以由复平面上单位圆中的椭圆完全刻画.     

含时量子动力学模拟的低存储龙格-库塔方法

A wide range of quantum systems are time-invariant and the corresponding dynamics is dictated by linear differential equations with constant coefficients.Although simple in mathematical concept,the integration of these equations is usually complicated in practice for complex systems,where both the computational time and the memory storage become limiting factors.For this reason,low-storage Runge-Kutta methods become increasingly popular for the time integration.This work suggests a series of s-stage sth-order explicit RungeKutta methods specific for autonomous linear equations,which only requires two times of the memory storage for the state vector.We also introduce a 13-stage eighth-order scheme for autonomous linear equations,which has optimized stability region and is reduced to a fifth-order method for general equations.These methods exhibit significant performance improvements over the previous general-purpose low-stage schemes.As an example,we apply the integrator to simulate the non-Markovian exciton dynamics in a 15-site linear chain consisting of perylene-bisimide derivatives.