Shifts of the 4snd 1,3DJ Levels of the Naturally Abundant, Even Ca Isotopes

Abstract

The level isotope shifts of the 4snd 1,3DJ have been measured in the singlet-triplet mixing region around n = 15 applying the resonant Doppler-free 2-photon laser spectroscopy and the thermionic diode as a detector. From the isotope shift as well as from the intensities of the lines the singlet-triplet mixing was found to be larger than previously determined from fine structure measurements and the study of the hyperfine structure in the odd isotope 43Ca.