ON THE ELASTIC PROPERTIES OF LITHIUM, SODIUM AND POTASSIUM OXIDE - AN ABINITIO STUDY

The binding energy, equilibrium lattice parameter, elastic constants and central zone phonon frequencies of Li2O, Na2O and K2O have been calculated at an ab initio level with CRYSTAL, a Hartree-Fock linear combination of atomic orbitals (LCAO) program for periodic compounds. The variational basis set has been optimized for each compound, and is reported for future reference and work. A quite satisfactory agreement with very recent experimental data is obtained for Li2O. With regard to Na2O and K2O no experimental data exist, to our knowledge, for the elastic constants and the central zone phonon frequencies, so that the present data represent the first determination of these quantities.