Photoacoustic Spectra of Complexes of Erbium (III) with Glycine and Alanine

The crystals of the complexes Er(Gly)₃Cl₃. 3 H₂O and Er(Ala)₃Cl₃. 3 H₂O were synthesized and the photoacoustic (PA) spectra in the 300–800 nm region are reported. Their PA and absorption spectra are interpreted. The PA relative intensities represented by intensity branching vectors and the perturbation of ligands on the energy levels of Er³⁺ ion are discussed. The fluorescene properties of Er(Gly)₃Cl₃. 3 H₂O and the relaxation process models were also studied based on the PA and absorption spectra.