ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 17, Number 6
JKCSEZ 17(6)
December 20, 1973 

By use of an Integral Hellmann-Feynman formula, the cubic crystal field splitting 1O Dq in KNiF3 is calculated from first principles. Numerical values of covalency parameters and necessary integrals are quoted from Sugano and Shulman. The result, 7100cm-1, is in excellent agreement with the observed value, 7250cm-1. It is found that higher order perturbation energy correction is of the same order of magnitude as 10 Dq itself and is, therefore, essential tin calculating 10 Dq from first principles. It is also found that the point charge potential is the dominant part of the crystal field potential.