High-lying bound Rydberg states of excited Hg(6s6p3P1) atoms from two-color resonance ionization mass spectroscopy

Mercury isotopes are investigated with two-color resonance ionization mass spectroscopy (RIMS). Isotope shifts, hyperfine structure splittings, and the lifetime of the intermediate 6s6p P-3(1) State are determined by RIMS. Ion yields at the threshold region in various static electric fields are measured in order to determine an extrapolated ionization energy value at zero field strength. New energy values for high-lying bound 6s nd D-3 (21 < n <70) Rydberg states of Hg isotopes are found under field-free conditions and with delayed, pulsed electric field ionization. To the author' knowledge this is the first time that isotopic effects on the ionization energy are deduced from the convergence limit of the Rydberg series.