Vibrational study of Li6P6O18 center dot 3H(2)O and ab initio calculations in P6O18 and P6O18 center dot 3H(2)O

摘要

The infrared and polarized Raman spectra of the trigonal Li(6)P(6)O(18.)3H(2)O crystal are reported. The results are analysed using several group theory approaches, in terms of internal and external modes of the highly symmetric P6O18 cyclophosphoric ring and water molecules. Equilibrium geometnes and vibrational spectra of P6O18 units, free and in interaction with watermolecules (P6O18.3H(2)O) have been determined by ab initio calculations using the basis set 6-31+G(d) of Hartree Fock method. Experimental frequencies and polarisation conditions are remarkably consistent with ab initio calculations. A detailed description of the normal modes of vibration of these systems is presented. (C) 2003 Elsevier B.V. All rights reserved. [References: 21]