Calculation of normal molecule vibrations of organic phosphorus compounds and complexes forming during extraction of uranium, plutonium and other heavy metals

Frequencies and shapes of normal vibrations of U and Pu nitrates, carbonates, sulphates, and phosphates (simple salts and complexes) have been computed, using the model of coordination and polarization of anions (molecules). A complete computation of frequencies and shapes of normal vibrations for different isomer molecules of free trimethylphosphate has been performed as well as computation of frequencies and shapes of vibrations of triethylphosphate and models of tri-n-butylphosphate: (C2H4R29O)3PO, (R57O)3PO, and (n-C4H9O)(R57O)2PO. The computations performed have been used for complete theoretical interpretation of the frequencies of tri-n-butylphosphate vibrations. The causes of partial polarization of the compounds in the process of complexing are discussed. The data obtained have shown that changes in vibration frequencies during complexing can be described correctly if the effects of coodination and partial polarization on the vibrations of complexes are taken into account. A specific nature of interaction between electron shells of the oxygen atoms in phosphoryl and carboxyl bonds causes a change in polarization