Optical properties and electron zone structure of AnXO4 single crystals

A possibility of application of the Harrison's modification of the Linear Combination of Atomic Orbitals method to the set of crystals A n XO 4 (n equals 1,2; A equals K, Pb; X equals W, Cr S) and to molecular clusters CrO 4 2- is investigated. Calculation of energetic structure for lead tungstate and regular chromate anion and it's comparison with experimental data allowed to determine the values of semiempiric parameters, suitable for calculations by Harrison's method for complex crystals. Energy calculations are carried out for deformed CrO 4 2- clusters, for potassium chromate K 2 CrO 4 and for isostructural to it potassium sulfate K 2 SO 4 in order to clarify the crystal surrounding influence to the CrO 4 2- molecular complexes energy levels and also to arrange the genesis of energy zones.