Single-bubble sonoluminescence of aqueous solutions of lanthanide chlorides and models of the sonochemistry of nonvolatile metal salts

摘要

The single-bubble sonoluminescence of d-f (Ce~(3+), Pr~(3+)) and f-f (Tb~(3+)) ions is detected in aqueous solutions of LnCl_3. It has been shown that the luminescence of these ions is sonophotoluminescence, i.e., the reemission of the absorbed short-wavelength part of the radiation spectrum of a blackbody, which appears in a bubble levitating in the field of a standing ultrasonic wave, in the bulk of the solution. In view of the revealed inefficiency of reemission in GdCl_3, the single-bubble sonoluminescence of Gd~(3+) has not been observed. The results indicate the low probability of the penetration of nonvolatile metal ions into the bubble in the hot shell model, which would be valid in single-bubble sonolysis and thereby confirm the validity of the injected droplet model, which explains the penetration to the bubble, electronic excitation, and luminescence of f-f ions Gd~(3+) and Tb~(3+) in multibubble sonolysis with an intensity much higher than the yield of their sonophotoluminescence.