CRYSTAL-FIELD THEORY OF MAGNETIC-BEHAVIOR OF ER-2(SO4)(3)CENTER-DOT-8H(2)O

Using the most rigorous approach of direct diagonalization of the Hami ltonian matrix constructed in the complete basis states (364 in number ) of tile Er3+ ion the observed magnetic susceptibility and anisotropy data of erbium sulphate octahydrate were simulated and the set of cry stal field parameters was evaluated. This procedure automatically incl udes the effect of intermediate coupling and the J-mixing under the cr ystal field. It was also demonstrated that such rigorous calculation u sing complete basis states is necessary in order to evaluate the corre ct set of parameters which may widely differ from the values obtained from approximate calculations previously performed using partial numbe r of basis states of the ion concerned.