On the emitters of sulfuric acid sonoluminescence

A comparative study of the sonoluminescence spectra of water and argon-saturated aqueous H₂SO₄ solutions was carried out. At an H₂SO₄ concentration of 18 mol L⁻¹, the sulfuric acid sonoluminescence is fifty times more intense than water sonoluminescence. The sulfuric acid luminescence spectrum differs from the water sonoluminescence spectrum caused by the emission of excited water molecules and OH radicals from the gas phase of cavitation bubbles. The sulfuric acid sonoluminescence spectrum exhibits maxima at 330, 420, 500, and 630 nm. Emitters of sonoluminescence of sulfuric acid are the singlet (330–340 nm) and triplet (∼420 nm) excited SO₂ molecules formed by sonolysis of H₂SO₄ molecules. Another product of sonolysis of H₂SO₄, atomic oxygen, is assumed to be responsible for the luminescence at λ = 630 nm. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1742–1745, August, 2005.