Spin-Hamiltonian parameters and angular distortion for the trigonal Nd3+ center in congruent LiNbO3

The 52 x 52 energy matrix related to the ground multiplet I-4(9/2) and the first to third excited multiplets I-4(11/2), I-4(13/2) and I-4(15/2) for 4f(3) ions in trigonal crystal field under an external magnetic field is established. By diagonalizing the energy matrix, the spin-Hamiltonian parameters (g factor g(//),g(perpendicular to) and hyperfine structure constants (143)A(//), (143)A(perpendicular to), (145)A(//), (145)A(perpendicular to)) of the trigonal Nd3+ center in congruent LiNbO3 crystal are calculated. The calculated results are in reasonable agreement with the experimental values. From the calculations, the negative signs of hyperfine structure constants are suggested and the angular distortion of the trigonal Nd3+ center in LiNbO3, which is unable to be determined by EXAFS measurement, is obtained. The results are discussed. (C) 2010 Elsevier B.V. All rights reserved.