MNDO study of refractive index and dispersion of P sub(2)O sub(5) glass

The geometry, refractive indices and dispersion of the H sub(4)P sub(2)O sub(7) structural unit were calculated by the MNDO CI (configurational interactions) semi-empirical molecular orbital method. The optimized geometry and calculated properties showed a good agreement with the experimentally determined data. The absorption edge was found to be 100 nm. Using Sellmeier's dispersion formula with the assumption that lambda sub(1) = 100 nm and n sub(D) = 1.503, a number of refractive indices of P sub(2)O sub(5) glass and then dispersion coefficient were calculated. Abbe value, v sub(D), proved to be 60.6, which was in a good correlation with experimental data determinated by Kordes (60.6). It was concluded that the MNDO CI approach may be employed for estimating optical properties of different oxides and materials when direct measurements are not available.