Oana C Melania, Krylov Anna I
Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, USA.
J Chem Phys. 2007 Dec 21;127(23):234106. doi: 10.1063/1.2805393.
Implementation of Dyson orbitals for coupled-cluster and equation-of-motion coupled-cluster wave functions with single and double substitutions is described and demonstrated by examples. Both ionizations from the ground and electronically excited states are considered. Dyson orbitals are necessary for calculating electronic factors of angular distributions of photoelectrons, Compton profiles, electron momentum spectra, etc, and can be interpreted as states of the leaving electron. Formally, Dyson orbitals represent the overlap between an initial N-electron wave function and the N-1 electron wave function of the corresponding ionized system. For the ground state ionization, Dyson orbitals are often similar to the corresponding Hartree-Fock molecular orbitals (MOs); however, for ionization from electronically excited states Dyson orbitals include contributions from several MOs and their shapes are more complex. The theory is applied to calculating the Dyson orbitals for ionization of formaldehyde from the ground and electronically excited states. Partial-wave analysis is employed to compute the probabilities to find the ejected electron in different angular momentum states using the freestanding and Coulomb wave representations of the ionized electron. Rydberg states are shown to yield higher angular momentum electrons, as compared to valence states of the same symmetry. Likewise, faster photoelectrons are most likely to have higher angular momentum.
本文描述并通过实例展示了用于单双取代耦合簇和运动方程耦合簇波函数的戴森轨道的实现。同时考虑了基态和电子激发态的电离情况。戴森轨道对于计算光电子角分布、康普顿轮廓、电子动量谱等的电子因子是必要的，并且可以解释为出射电子的状态。形式上，戴森轨道表示初始N电子波函数与相应电离系统的N - 1电子波函数之间的重叠。对于基态电离，戴森轨道通常与相应的哈特里 - 福克分子轨道（MOs）相似；然而，对于电子激发态的电离，戴森轨道包含多个MOs的贡献，其形状更复杂。该理论应用于计算甲醛基态和电子激发态电离的戴森轨道。采用分波分析，利用电离电子的自由和库仑波表示来计算在不同角动量态中找到出射电子的概率。结果表明，与相同对称性的价态相比，里德堡态产生的电子角动量更高。同样，更快的光电子最有可能具有更高的角动量。
