论文标题
用于与所有单个激发的配置相互作用的分析梯度和衍生耦合，一个双重激发 - 在非绝热动力学的途中
Analytic Gradients and Derivative Couplings for Configuration Interaction with All Single Excitations and One Double Excitation -- En Route to Nonadiabatic Dynamics
论文作者
论文摘要
我们提供了分析梯度和衍生耦合，以实现最简单的多差配置相互作用方法，cis-1d，一种电子结构ANSATZ，其中包括所有单个激发和一个孤独的双重激发，在Hartree-Fock参考状态的顶部。我们表明，与标准CIS理论相比，所得方程在数值上是稳定的，需要评估相似数量的积分。一个人可以轻松地区分所需的边界轨道（$ \ mathtt {h} $和$ \ mathtt {l} $），而成本很小。所得算法已在QCHEM电子结构软件包中实现，对于使用$ s_ {0} $ - $ s_ {1} $ crossings理解光化学应立即有用。
We present analytic gradients and derivative couplings for the simplest possible multireference configuration interaction method, CIS-1D, an electronic structure ansatz that includes all single excitations and one lone double excitation on top of a Hartree-Fock reference state. We show that the resulting equations are numerically stable and require the evaluation of a similar number of integrals as compared to standard CIS theory; one can easily differentiate the required frontier orbitals ($\mathtt{h}$ and $\mathtt{l}$) with minimal cost. The resulting algorithm has been implemented within the Q-Chem electronic structure package and should be immediately useful for understanding photochemistry with $S_{0}$-$S_{1}$ crossings.
