Absorption, diffused reflection, transmission and photo-acoustic spectra of some praseodymium salts

The absorption, diffused reflection, transmission and photo-acoustic spectra of some trivalent praseodymium salts are reported. These spectra are obtained in 400–800 nm wavelength regions for powdered samples. These salts give well-known four peaks of Pr3+ at 447, 469, 483 and 596 nm wavelengths in absorption, reflection and transmission spectra and three peaks at 445, 473 and 596 nm in photo-acoustic spectra. These peaks arise due to transitions from ground level (3H4) to excited 3P2, 3P1, 3P0 and 1D2 levels, respectively. The recently developed photo-acoustic technique, where the detection is based on non-radiative transitions is found to be equally sensitive. The nephelauxetic parameters and branching ratios for different transitions are reported.