IS SONOLUMINESCENCE DUE TO COLLISION-INDUCED EMISSION

We estimate the collision-induced emission (CIE) intensity and profile in the visible and near UV region of the spectrum of N2-X pairs where X represents another N2 molecule or an argon atom, etc. of shock waves believed to exist in sonoluminescence experiments. Calculated profiles consist of superimposed high overtone bands and resemble the measured profiles. Intensities calculated on the basis of a few, simple assumptions concerning the induced dipole surface compare favorably with measurements. The agreement obtained suggests that CIE is an attractive alternative to bremsstrahlung to explain sonoluminescence. The CIE source is optically thin, and the spectral emission profile is not related to Planck's law. © 1994 The American Physical Society.