Ground and excited states of Li-, Be- through a density-based approach
Abstract
Density functional calculations are performed for ground [He]2s2 1Se, and three metastable bound excited states, 1s2s2p2 5Pe, 1s2p3 5So, 1s2s2p3p 5Pe of Li- and [He]2s2p2 4Pe, [He]2p3 4So, 1s2s2p3 6So of Be- each. The work-function-based exchange potential is used, while the correlation effects are included by employing the Lee-Yang-Parr potential. The relevant nonrelativistic KS equation is solved by means of a generalized pseudospectral discretization scheme offering nonuniform and optimal spatial grid. Computed total energies, radial densities, selected density moments, as well as two transition wavelengths (1s2s2p2 5Pe 1s2p3 5So of Li-, [He]2s2p2 4Pe [He]2p3 4So of Be-) show reasonably good agreement with the available theoretical and experimental data. The term energies show an absolute deviation of 0.007--0.171% with the largest deviation being observed for the even-parity 5P state of Li-. The transition wavelengths of Li-, Be- are calculated within 0.891 and 0.438% of the experimental values. This offers a simple practical route towards accurate reliable calculation of excited states of anions within density functional theory.