Malbon Christopher L, Zhu Xiaolei, Guo Hua, Yarkony David R
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Department of Chemistry, Stanford University, Stanford, California 94305, USA.
J Chem Phys. 2016 Dec 21;145(23):234111. doi: 10.1063/1.4971369.
For two electronic states coupled by conical intersections, the line integral of the derivative coupling can be used to construct a complex-valued multiplicative phase factor that makes the real-valued adiabatic electronic wave function single-valued, provided that the curl of the derivative coupling is zero. Unfortunately for ab initio determined wave functions, the curl is never rigorously zero. However, when the wave functions are determined from a coupled two diabatic state Hamiltonian H (fit to ab initio data), the resulting derivative couplings are by construction curl free, except at points of conical intersection. In this work we focus on a recently introduced diabatization scheme that produces the H by fitting ab initio determined energies, energy gradients, and derivative couplings to the corresponding H determined quantities in a least squares sense, producing a removable approximation to the ab initio determined derivative coupling. This approach and related numerical issues associated with the nonremovable ab initio derivative couplings are illustrated using a full 33-dimensional representation of phenol photodissociation. The use of this approach to provide a general framework for treating the molecular Aharonov Bohm effect is demonstrated.
对于通过锥形交叉点耦合的两个电子态，只要导数耦合的旋度为零，导数耦合的线积分可用于构建一个复值乘法相位因子，以使实值绝热电子波函数单值。不幸的是，对于从头算确定的波函数，旋度从未严格为零。然而，当波函数由耦合的两个非绝热态哈密顿量H（拟合从头算数据）确定时，除了在锥形交叉点处，所得的导数耦合在构造上是无旋的。在这项工作中，我们专注于一种最近引入的非绝热态方案，该方案通过在最小二乘意义上拟合从头算确定的能量、能量梯度和导数耦合到相应的由H确定的量来生成H，从而对从头算确定的导数耦合产生一个可消除的近似。使用苯酚光解离的完整33维表示来说明这种方法以及与不可消除的从头算导数耦合相关的数值问题。展示了使用这种方法为处理分子阿哈罗诺夫 - 玻姆效应提供一个通用框架。
