CALCULATING SPIN-ORBIT MATRIX-ELEMENTS WITH RACAH

RACAH is a computer program developed to simplify calculations involvi ng generalized coupling coefficients. As a demonstration of its useful ness in doing this, we apply it to calculating the spin-orbit matrix e lements of CrBr3. From those matrix elements we can derive the spin-or bit coupling coefficients, vital to discussing Kerr rotation. We base our calculations on a cluster consisting of a Cr3+ ion, surrounded by six Br- ions in an octahedral configuration. The Racah-Wigner calculus , useful for doing such calculations, is built into RACAH in such a wa y as to provide a natural approach to choosing between possible group chains. (C) 1996 Academic Press, Inc.