Power-dependent line shapes of transitions to autoionizing Rydberg states

Abstract

The line shapes of the $6sns$, $^{1}S_{0}\ensuremath{-}6{P}_{\frac{1}{2}}\mathrm{ns}$ transitions in Ba as a function of the laser intensity are modeled with the use of two-channel multichannel quantum-defect theory and the isolated-core-excitation model. An analytical expression for the line shape is derived and used to obtain a value of $|〈g|r|e〉|=4.1$ a.u. for the dipole transition moment of the ${\mathrm{Ba}}^{+}$ ionic $6s\ensuremath{-}6{P}_{\frac{1}{2}}$ transition, in agreement with a recent theoretical calculation.