Fine and hyperfine structure of the 2P2 term of Li6 and Li7

Interference signals in resonance fluorescence associated with the crossing of the J=32, mJ=-32 and J=12, mJ=12 fine-structure Zeeman levels were used to investigate the fine and hyperfine structure of the 2P2 term of Li6 and Li7. The magnetic field strength corresponding to this crossing was determined for each isotope to within 1 part in 4.5×104. However, the precision with which the fine-structure splitting can be inferred from the crossing field is limited at the present time by a lack of knowledge of relativistic and diamagnetic corrections to the orbital g factor gL. The Li7 signal exhibited well-resolved hyperfine structure. Measurements of this structure have been used together with Ritter's result for the hyperfine splitting in the 2P122 state to obtain values for ac,32 and ad,32, the Fermi contact and dipole-dipole contributions to the magnetic hyperfine interaction in the 2P322 state of Li7, and a value for Q, the quadrupole moment of the Li7 nucleus. They are: ac32=-10.53±0.23 Mc/sec, ad32=7.13±0.03 Mc/sec, and Q=(-3±2)×10-26 cm2. The widths of the hyperfine components of the Li7 crossing signal yield (2.72±0.04)×10-8 sec for the life-time of the 2P2 term of atomic lithium. © 1967 The American Physical Society.