Peculiarities of atomic lines in sonoluminescense spectra

Alkali-metal lines in SL spectra are broadened, asymmetrically shifted toward the red spectral region, unshifted narrow parent peaks are observed. The shape is influenced a number of parameters. The effects have no explanation. We model a line shape, assuming that line broadening arises from a density and line asymmetry results from superposition of spectra generated at different densities of a perturbing medium. Simulation shows that broad-band emission occurs within the density range of 10-400 Amg for KCl, LiCl, NaCl aqueous solutions under Ar at the ultrasound frequency of 20 kHz. The lower limit of the range shifts to higher density in order of K<Li<Na following the increase of exited state energy. The effect of surfactant on the shape of Na D-line is also observed, which probably indicates the essential influence of nano-size layers on the dynamics of emitting process.