Spin-adapted reduced-Hamiltonian theory: Application of the independent-pair model to the isoelectronic sequence of lithium

Publisher Website
Google Scholar
Abstract
The physical meaning of the eigenvectors of the spin-adapted reduced-Hamiltonian matrices inspires the independent-electron-pair model, which permits the direct evaluation of the second-order reduced density matrices. Recently we have tested this method for singlet states of the beryllium isoelectronic sequence. Here, this same approach is applied to the doublet isoelectronic sequence of the lithium atom. In all the cases the theoretical results have been compared with experimental data when available and with results obtained in a parallel way with a full-configuration-interaction treatment, and the agreement is very satisfactory.