Photoionization of lithium

The photoionization of lithium from threshold to 50 eV above threshold is calculated via the method of polarized orbitals. The method is applied in as orthodox a manner as possible; this means that total wave functions are constructed as by Temkin and Lamkin using only the static dipole part of the perturbation of core electrons by the outer part of the external electron. According to other previously given prescriptions, both initial (bound) and final (continuum) wave functions are so polarized, only the length form of the matrix is calculated, and bilinear terms from the polarization contributions are retained (although their effect in this calculation is small). The results themselves are essentially identical to those of a recent diagrammatic calculation of Chang and Poe (in the region below 5 eV where they have calculated), and as such they differ in certain significant components from exchange adiabatic and extended polarization results of Matese and LaBahn (although their over-all result is similar). Discussion of these points is included. The $s$- and $p$-wave $e$-${\mathrm{Li}}^{+}$ phase shifts, which are derived as by-products of this calculation, are also presented and compared to other phase-shift calculations.