Photoabsorption by Cesium

Oscillator strengths and the photoionization cross section for the ground state of cesium are computed using a semiempirical model potential involving two adjustable parameters and based only on the lowest few spectroscopic term values. The spin-orbit interaction is included in the model potential, and the effects of core polarization are explicitly taken into account in both the model potential and the dipole transition matrix element. The doublet-line-strength ratios for discrete transitions are in good agreement with Agnew's measured values, and no support is given other indications that the line strength for $6s\frac{1}{2}-\mathrm{np}\frac{1}{2}$ is vanishingly small somewhere in the region $n=10\mathrm{}-15$. Good agreement with two recent measurements of the spin-orbit effect in photoionization is also obtained. The oscillator strengths and photoionization cross section are significantly lower than the measured values of Agnew, and Marr and Creek, respectively, but the total atomic polarizability is in excellent agreement with a recent measurement.