Crystal field analysis of EuCl3 center dot 6H(2)O

Absorption and magnetic circular dichroism (MCD) spectra of polycrystalline EuCl3 . 6H(2)O samples were recorded between 16 000 and 36 000 cm(-1) at ambient temperature and at 77 K. A total of 104 crystal held transitions has been observed in the spectra. The MCD spectrum resembles the first derivative of the absorption spectrum, indicating the presence of (pseudo) A-terms. The advantage of MCD is the possibility of detecting quasi-degenerate crystal field levels, which are not resolved in the absorption spectrum. The coordination polyhedron around Eu3+ is a distorted square antiprism (C.N. = 8). In order to make the crystal held calculations more tractable, the real C-2 symmetry of the europium site is approximated by a C-2v symmetry. The energy levels of the 4f degrees configuration of Eu3+ are parametrized in terms of 20 free ion parameters and 9 B-q(lambda) crystal field parameters. J-mixing is taken into account.