The photoacoustic spectra of 1-tyrosine hydrazide, 8-hydroxyquinoline and ammonium metavanadate complexes containing Pr, Nd, Er and Ho have been recorded in the 400–800 nm region using a single beam photoacoustic spectrometer. The main spectral features in the photoacoustic spectra are found to be due to triply ionized rare-earth atoms and the assignments reveal a red shift in their spectral features as compared to their positions in the free ions. These shifts have been used to calculate the nephelauxetic parameters for these complexes. The photoacoustic branching ratios have also been determined and compared with absorption branching ratios for some of these complexes.
