Response to “Comment on ‘Sonoluminescence light emission’ ” [Phys. Fluids 12, 472 (1999)]

n In their Comment, Hammer and Frommhold 1 check the validity of the results in the original publication 2 by comparing the approximate calculations found therein to their ab initio, quantum mechanical formalism. Overall, both comp tational methods yield similar results, which validates t assumptions about the principal physical processes invo in SBSL light emission~electron–ion and electron–neutr bremsstrahlung, radiative recombination ! made in Ref. 2. When employing the quantum mechanical absorption coe cients, Hammer and Frommhold obtain spectra that stronger in the UV than the approximate results, and dominated by electron–neutral bremsstrahlung through the range of observable wavelengths. This leads to a cha in the spectral shape, and, in particular, removes the spe maximum obtained in the approximate calculations for gon. It should be pointed out here that the approximate f malism can produce this change in spectral shape as w upon even slight changes of the external parameters ~driving pressure amplitude, ambient bubble radius !. In particular, for a xenon bubble we predict ~see Fig. 1! that increasingPa by a very small amount ( ;0.01 atm! produces a noticeable shi