The single-bubble sonoluminescence of d-f (Ce³⁺, Pr³⁺) and f-f (Tb³⁺) ions is detected in aqueous solutions of LnCl₃. 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 GdCl₃, the single-bubble sonoluminescence of Gd³⁺ 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 Gd³⁺ and Tb³⁺ in multibubble sonolysis with an intensity much higher than the yield of their sonophotoluminescence.

Luminescence bands of Tb3+ and Gd3+ ions are detected during sonolysis in the regime of a moving single bubble in aqueous solutions of TbCl3 and GdCl3 salts with concentration 1–2 mol/L. Saturation wi

Lines of Ne (3p-3s, 550–800 nm) and Xe (6p-6s, 800–1050 nm; 7p-6s, 475 nm) have been detected in the mechanoluminescence spectrum of terbium and cerium sulfate crystallohydrates. The luminescence of noble gas is observed jointly with the known bands of Ce³⁺ and Tb³⁺ ions and N*₂ lines. The lines corresponding to excited Xe⁺ ions (500–550 nm), indicative of achievement of electric-field strengths on the order of 10⁷ V/cm during mechanoluminescence, are also observed. It is established that, during mechanoluminescence of Tb₂(SO₄)₃ · 8D₂O in an argon atmosphere under a pressure of 1.3 atm, mechanochemical reactions of decomposition of crystallization water (D₂O) molecules cause luminescence of OD radicals; this luminescence is initiated by electron impact occurring during electrization and in discharges in crystals during destruction.

The luminescence of TbCl₃ · 6H₂O and Tb(acac)₃ · H₂O crystal hydrates under conditions of multibubble sonolysis (20 kHz, 25 W) of the corresponding crystal suspensions in perfluorodecalin and undecane has been observed for the first time. The luminescence spectra contain the lines of emission from Tb³⁺* ions. No emission lines due to molecular nitrogen have been observed in N₂-saturated suspensions. Based on a comparison of the emission accompanying the sonolysis of suspensions, the photoluminescence of terbium crystals, and the tribolumninescence under usual mechanical actions, it is concluded that the nature of the observed phenomenon corresponds to sonotriboluminescence (STL), the mechanism of which is different from that of the recently discovered STL of resorcinol where N₂ is predominantly excited. It is suggested that resorcinol-like organic crystals and terbium compounds belong to different types of triboluminescent materials, which are characterized by different susceptibilities to STL activation during the sonolysis of suspensions.

It is for the first time that we have obtained emission-line spectra of metal atoms during single-bubble sonoluminescence of metal carbonyl W(CO)6, Mo(CO)6, Cr(CO)6 solutions in dodecane and similar spectra during single- and multibubble sonoluminescence of nanodispersed Cr(CO)6 suspensions in water, 83% H2SO4 and 74% H3PO4. Nanodispersed suspensions with an average particle size of 15-20 nm were obtained through sonodispersing and filtering Cr(CO)6 crystals in water. The method for comparing the intensities of two atomic metal lines made it possible to measure the electronic temperatures achieved in cavitation bubbles under different modes of sonolysis that vary in the range of (4.5-16)·103 K depending on the mode of sonolysis, the type of liquid and saturating gas (He, Ar, Kr) and the acoustic energy entering the solution or suspension. The electronic temperature for multibubble sonoluminescence is, on the average, by (2-2.5)·103 K less than for single-bubble sonoluminescence for all liquids in question.