Optical study of praseodymium dicarboxylate [Pr(H2O)]2[O2C(CH2)3CO2]3.4H2O

Abstract Praseodymium dicarboxylate, [Pr(H 2 O)] 2 [O 2 C(CH 2 ) 3 CO 2 ] 3 .4H 2 O]–glutarate, Pr[glut], is synthesized by hydrothermal techniques. The title compound crystallizes in the monoclinic space group C2/c (No. 15). The rare earth cation is coordinated by nine oxygen atoms, eight oxygen atoms from the carboxylate groups and one from the water molecule. The local symmetry of Pr site is low, C s . The absorption spectra of Pr[glut] are recorded from the visible to the far IR domain at 300, 77 and 9 K. Under various Ar + laser excitations no emission is detected from 3 P 0 and 1 D 2 excited levels of Pr 3+ ion. In the low temperature absorption spectra only one electronic line is recorded for 3 H 4 → 3 P 0 transition. It confirms a unique local environment for the rare earth ion in Pr[glut]. The utility of the ‘barycenter curves’ in the attribution of electronic lines is demonstrated. Energy level scheme of 36 Stark components is deduced from the absorption spectra. The parametric calculation was performed on the whole 4f 2 (Pr 3+ ) configuration with the starting set of crystal field parameters obtained previously for the Eu 3+ ion in the isostructural compound. Eight free ion and nine phenomenological crystal field parameters in C 2v symmetry reproduce quite well several electronic levels of Pr 3+ ion experimentally observed in Pr[glut]. A good r.m.s. standard deviation of 14.8 cm −1 is obtained.