EXPERIMENTAL

The absorption spectra of six Nd3+ ternary amino acid complexes have been recorded in water. Nine baiids in the region 400-800 nm have been observed. Slater-Condon. Lande ' spin-orbit interaction and Judd-Ofelt intensity parameters from the observed bands have been computed. Using these parameters energies and intensities of these bands have been calculated. The agreement between the calculated and observed values is good. The variation of al1 the parameters in the complexes from the corresponding Nd3 ' aquo ion parameters has been discussed. Using Ft values. the SPECi'ROSCOPIC m I E S OF ~ d ~ * TERNARY AMINO ACID COMPLEXES water. The inter-electronic repulsion. spin-orbit interaction. nephelauxetic effect and bonding in various complexes have been discussed in the light of Slater-Condon (Fb), LandeP(CAs), nephelauxetic rat io (B) and bonding (bl") parameters. The Judd-Ofelt intensity parameters (TI) have also been calculated from the observed oscillator strengths of the various f-f transitions studied in the visible region. These have been further co-related with the co-ordination from different donors in the complexes. For the calculation of various parameters, partial regression method 1101 has been used. nephelauxetic ra t io and bonding parameter have been computed which indicate covalent character in these complexes