OPTICAL-PROPERTIES OF IMPURITY ATOMS IN PRESSURIZED SUPERFLUID-HELIUM

We report on the optical properties of alkali atoms (Cs and Rb) in the pressurized superfluid helium. We observed excitation and emission sp ectra at various pressures from the saturated vapor pressure to about 25 atm. The theoretical calculations on the basis of the atomic bubble model have also been worked out. The qualitative agreement between th e theoretical and experimental results with respect to the peak shift, the linewidth, and their pressure dependence is achieved in the frame work of the spherical atomic bubble model. The D-2 excitation spectra with the double peaks are interpreted qualitatively in terms of the Ja hn-Teller effect, indicating the existence of the nontotally symmetric al density distribution of the surrounding helium atoms.