Measurement of the acoustic nonlinearity parameter B/A in solvents:: Dependence on chain length and sound velocity

This work consists of a systematic study of the acoustic nonlinearity parameter (BIA) in I-alkanols from methanol to l-decanol, ketones from acetone to methyl hexyl ketone, and alkyl acetates from ethyl to octyl acetate. By focusing a 14-MHz tone burst through a spherical quartz lens in each solvent, the second harmonic is generated and measured by a 28-MHz transducer at various distances from the focus. This provides the point of maximum second harmonic power, and enables the computation of the nonlinear parameter using a simple model. The BIA values thus obtained are in reasonable agreement with these available in the literature. The BIA values are found to increase with chain length and sound velocity, this increase being in contradiction with Ballou's rule. Moreover, a hybrid model based on Schaaffs' formula for sound velocity fits the experimental results, questioning the validity of Ballou's rule for solvents within a single chemical family. (C) 2000 Acoustical Society of America. [S0001-4966(00)04211-9].