Electron-atom bremsstrahlung and the sonoluminescence of rare gas bubbles

Abstract

The bremsstrahlung spectra of electrons interacting with neutral rare gas atoms are calculated for temperatures from 5000 to 40 000 K. The calculations were previously shown to be in agreement with measurements of such spectra recorded under a variety of conditions. The computational results are compared with measured sonoluminescence (SL) spectra of rare gas bubbles. For the heavier rare gases, computed intensities and spectral line shapes compare favorably with the measurement at electron ``temperatures'' of roughly 20 000 K. The agreement suggests that electron--neutral-atom bremsstrahlung may be a principal mechanism of the light emission of rare gas SL bubbles if a weakly ionized SL environment may be assumed.