Oscillator Strength of Ionizing Transitions

Wallace L. Glab, Munir Hasan Nayfeh

D. C. Morton, Qixue Wu, G. W. F. Drake

Nikolai B. Delone, В. П. Крайнов

Sami Ul Haq, Mazhar Ali Kalyar, M. Rafiq +3 more

We report the experimentally determined oscillator strengths for the $5s6s$ ${^{1}S}_{0}\ensuremath{\rightarrow}5snp$ ${^{1}P}_{1}$ Rydberg transitions of strontium using two-step excitation in conjunction with a thermionic diode ion detector. The absolute photoionization cross section from the $5s6s$ ${^{1}S}_{0}$ excited state has been determined by adjusting the polarization vector of the ionizing laser beam parallel, perpendicular, and at the magic angle with respect to that of the exciting dye laser. The measured absolute value of the photoionization cross section $0.9\ifmmode\pm\else\textpm\fi{}0.2\text{ }\text{Mb}$ at the $5s$ threshold is used to extract the $f$ values of the $5s6s$ ${^{1}S}_{0}\ensuremath{\rightarrow}5snp$ ${^{1}P}_{1}$ $(26\ensuremath{\le}n\ensuremath{\le}73)$ Rydberg transitions. The oscillator strength in the discrete region merges smoothly to the oscillator strength density at the ionization threshold.

Lianjun Zheng

Limei Wang, Xiao-Meng Liu, Hao Zhang +4 more

The oscillator strengths of 6 P 3/2 → n S / n D transitions are measured by fitting ultracold Cs Rydberg atom field-ionized spectra. The oscillator strength ratios η( n ) = f D 5/2 ( n )/ f D 3/2 ( n ) and ρ( n ) = f S 1/2 ( n + 2)/ f D 3/2 ( n ), which agree with the calculations based on the wave functions obtained by Numerov's method, are determined. The obtained results indicate that the ratios are almost independent of the principal quantum number n .