Measurements of the Rydberg Transition Energies for the n1S0 State and the Ionization Potential for 40Ca Atoms.

Two-photon spectroscopy has been applied to measure the Rydberg transition energies in the n1S0 state of 40Ca atoms at n = 40–120. The ionization potential determined from these experimental data is 49305.91966(4) cm−1. Using the frequency-doubled radiation and fundamental radiation from a diode laser, the frequencies of two-photon transitions to Rydberg states with the principal quantum numbers of 75 and 76 have been measured simultaneously with the frequencies of resonances of saturated absorption in a rubidium vapor cell. The chosen transition frequencies for rubidium atoms are known with high accuracy. Such frequency references make it possible to improve the accuracy of determination of the Rydberg transition energies in 40Ca atoms. [ABSTRACT FROM AUTHOR]