Magnetic Hyperfine Structure and Core Polarization in the Excited States of Lithium
Abstract
The magnetic hyperfine splitting constants, a_{J}, from theoretical calculations on the 3^{2}S, 2^{2}P, 3^{2}P, and 3^{2}D excited states of the Li atom are reported. The wave functions were calculated using the author's GF method, which corresponds to optimizing the orbitals of a Slater determinant after spin projection. Thus the wave functions include core polarization, but no appreciable correlation. For the 2^{2}P state we calculate a_{12}=0.2206 a.u. (45.74 Mc/sec for ^{7}Li) which is in good agreement with the experimental value, 0.2227 +/ 0.0017 a.u. (46.17 +/ 0.35 Mc/sec for ^{7}Li), and the value from configuration interaction calculations, 0.2206. Thus for the Li atom core polarization accounts for most of the error in the HartreeFock values of a_{J}. These calculations yield <1r^{3}> and spin density, Q(0), in agreement with other accurate theoretical calculations, and in disagreement with the values found using level crossing experiments, indicating that the interpretation of the level crossing experiments in terms of <1r^{3}> and Q(0) may not be correct. It is found that for both the unrestricted HartreeFock and GF methods the use of a different Hamiltonian for each electron leads to virtual orbitals which are good approximations to the actual orbitals of excited states.
 Publication:

Physical Review
 Pub Date:
 December 1968
 DOI:
 10.1103/PhysRev.176.106
 Bibcode:
 1968PhRv..176..106G