Calculation of photoionization differential cross sections using complex Gauss-type orbitals
Calculation of photoionization differential cross sections using complex Gauss-type orbitals
复制标题
使用复杂高斯型轨道计算光电离微分截面
DOI：
10.1002/jcc.24848
复制
发表时间：
2017
影响因子：
3
通讯作者：
Yabushita Satoshi
中科院分区：
文献类型：
--
作者：
Matsuzaki Rei;Yabushita Satoshi
一般分子光电子角分布的精确理论计算已成为各种化学反应实时成像的重要工具。本文表明，利用复高斯型轨道（cGTO）基函数不仅可以精确地计算光电离总截面，还可以精确地计算光电子角分布。我们的方法可以很容易地与现有的量子化学技术相结合，包括电子相关效应，并适用于各种分子。应用所谓的二势公式来表示分子坐标系中从初始束缚态到最终连续态的过渡偶极矩。用复基函数的方法，用合适的cgto和传统的实高斯型轨道（gto）的混合物，变分地得到了两个必需的连续体函数，即零阶最终连续体态和光子场诱导的一阶波函数，以表示连续体轨道和剩余的束缚轨道。通过拟合出射库仑函数，优化了cgto的复轨道指数。通过计算和的不对称参数和分子框架光电子角分布，证明了当前方法的有效性。在计算中，采用了静态交换和随机相位近似，并讨论了结果与基函数的关系。©2017 Wiley期刊公司
Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss‐type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so‐called two‐potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth‐order final continuum state and the first‐order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss‐type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular‐frame photoelectron angular distributions of and . In the calculations of , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc.