# Atomic Bethe-Goldstone calculation of the hyperfine structure of Li(2P2)

## Abstract

A variational formulation of Brueckner's theory has been applied to the calculation of hyperfine parameters for the 2 P2 excited state of atomic lithium. The hierarchy of nth-order (or n-particle) Bethe-Goldstone equations defined previously has been modified so that complete electronic configurations occur at each level of the hierarchy. Thus L→2, S→2 eigenfunctions could be used throughout the calculations, although for practical reasons such functions are not explicitly constructed. Each net increment of any mean-value electronic property defined within the hierarchy is shown to be equivalent to a sum, to infinite order, of a certain well-defined set of linked diagrams in the many-particle perturbation theory. Computed results are in excellent agreement (within roughly 1%) with experimental data and with a previously published accurate perturbation calculation. © 1970 The American Physical Society.