This computer package was first developed by Y.Y. Yeung (see {YR92} and {YR93}) to calculate the energy levels and statevectors for any transition metal ions with the 3d^N configuration (N = 1 to 9) doped at orthorhombic or higher symmetry sites. It can be used to predict, analyze and correlate some optical spectroscopy data with electron paramagnetic resonance data as well as magnetic susceptibility data. It involves full diagonalisation within the 3d^N configuration of a complete crystal field Hamiltonian which consists of the electrostatic repulsion (with the Slater integrals or the Racah parameters) among those 3d electrons, the spin-orbit interaction (z parameter) and the Trees correction (a parameter) describing the two body orbit-orbit polarization interaction as well as the crystal field Hamiltonian (B_kq parameters). Explicit forms of the corresponding Hamiltonians and formulas for evaluating their matrix elements can be found in {YR92}. By incorporating the "imaginary" crystal field terms (see {CRY94}), this package has been extended to deal with any 3d^N ion located at sites with symmetry given by any of the 32 crystallographic point groups.¡@

        In essence, this package is composed of four computer programs applicable for the orthorhombic or higher symmetry sites (with real crystal field parameters) and arbitrary low symmetry sites (with complex crystal field parameters) in either the |d^N aSM_SLM_L> basis or |d^NaSLJM_J> basis. Those programs were written in the Microsoft QuickBasic language and executable in the DOS environment of any 286 (or above) personal computer system. There were also two libraries of efficient subroutines specifically developed to handle the matrix operations and the calculations of the 3j, 6j and 9j symbols. Besides, reduced matrix elements for all tensor operators (except the Trees correction) had been calculated and their numerical values, in double precision, were stored in some data files to save computing effort for recalculation. Some example files of input parameters and output energy levels and statevectors etc. were also included in this package to enable the users to get familiar with this package.
This computer package is obtainable from Y.Y. Yeung who can be contacted by email at dr.yeung@physics.org