Calculated crystal field parameters in RCo(5) and RNi(5) systems

We report an ab-initio calculation of the crystal field parameters B-lm of rare earth (R) ions in intermetallic RM(5) compounds (M = Ni, Co). The parameter with given l and m is calculated by integrating the product of the aspherical (1, m) component of the crystal potential and the radial density of 4f electrons of the rare earth ion. The potential results from the self-consistent calculation of the electronic structure of RMS using the full potential LAPW method, while the density of the 4f electrons is taken from an LSDA-SIC atomic calculation, in which the electron occupation numbers are fixed to their values in the corresponding RM(5) system. The sensitivity of results to the parameters which enter the calculation is tested.