BROADENING, SHIFTING AND ASYMMETRY OF THE STRONTIUM RESONANCE LINE INDUCED BY RARE-GAS PERTURBERS

A complete systematic study of the broadening and shifting of the Sr resonance line (5(1)P1-5(1)S0) by collisions with all five rare gases has been conducted with a high-resolution laser-induced fluorescence method. The method enabled us to measure, for the first time, asymmetries in the near wings of the Sr emission profiles. The measurements were performed at 720 K and pressures below 600 Torr. Our values of the line asymmetry are compared with ones predicted from lineshape models. Quantitative comparisons of the measured and theoretical line asymmetries suggest that atomic interactions in the Sr-rare-gas systems may not be entirely due to van der Waals type interactions, and that correlations between thermal motions and collisional interactions could be the major source of the spectral line asymmetry.