Tb(III) line intensities in multibubble sonoluminescence.

We observed the line emissions of trivalent terbium [Tb(III)] ions during multibubble sonoluminescence (MBSL) in the aqueous solutions of terbium chloride (TbCl) under argon gas atmosphere. The line intensities of excited Tb(III) ions increased with TbCl concentration(mass percentage) in aqueous solutions. This phenomenon was interpreted qualitatively by numerically computing the Tb(III) line intensities in one sonoluminescing bubble among the cavitation bubbles in a liquid. The driving pressure for this sonoluminescing bubble was obtained by numerically solving the cavitation dynamic equation and bubble-pulsation equation. The Tb(III) ion line intensities obtained from the sonoluminescing bubble were attained by solving computing fluid dynamics equations and the spectral radiation formula.