On the lifetime of the 2p level and the dipole polarizability and hyperpolarizability of lithium

A one-electron model for lithium is used to calculate the radiative lifetime of the resonance 2p level and the ground-state dipole polarizability. The model includes dipole, quadrupole and octupole K-shell excitations, asymptotic corrections of order r(-6) to the dipole operator and dynamical effects. The results are consistent with most other recent calculations and with a very recent measurement via photoassociative spectroscopy, but are not consistent with an earlier precise fast-beam laser measurement. The predicted hyperpolarizability of Li is in satisfactory accord with estimates from two extensive ab initio calculations.