Phase Resolution Method of PA Spectra in Copper(II)-EDTA Complexes

The complexes crystals of Cu(H₂EDTA) · H₂O and CaCu(EDTA) · 4 H₂O were synthesized and their photoacoustic spectra were determined in the region of 300–800 nm at room temperature. A method used to directly monitor both position and strength of the absorption bands of respective electronic states were proposed. With the amplifier and phase spectra all absorption peaks of different electronic states could be distinguished. The PA spectra were also explained by the 3d orbit radial scaling theory. All the d-d transition absorption peaks calculated are in good agreement with the experimental values. In addition, the non-radiative relaxation process and the relaxation time of excitation electron were discussed with the PA spectra.