Short-range structure of vitreous PO by MD simulation

Suzuki, Yoshihiro*; Takase, Keiichi*; Akiyama, Isao*; Suzuya, Kentaro; Umesaki, Norimasa*; Otori, Norikazu*

We have performed the molecular dynamics (MD) simulations for vitreous PO using isotropic pair potentials composed only of coulombic and repulsive interaction. The obtained P-O pair distribution function reproduced the two peaks expected from the results of neutron diffraction experiments, in the nearest-neighbor P-O correlation. The neutron-weighted real-space correlation function were also in semi-quantitative agreement with that from the experimental results. The distribution of coordination number for O around P and P around O showed that most P atoms form tetrahedral PO units in the glass and three-fifths of O atoms are bridging oxygen, O, and the others are terminal one, O. The pair distribution functions for P-O and P-O clarified the PO units have three long P-O bonds and one short P-O bond. We have concluded that the short-range structure for vitreous PO agrees well with the picture derived from many experiments.