Computational studies of crystalline H3PO4

A polarized split-valence wavefunction was computed for the H3PO4 molecule at its neutron crystallographic valence geometry, and the wavefunction was used to map the molecular electron-density distribution and to simulate X-ray crystal structure factors for both static, at-rest and dynamic thermally averaged structures. The thermal vibrational averaging was approximated using anisotropic mean-square atomic displacements from approximately 300 K neutron diffraction data. The simulated X-ray data were used to test pseudoatom multipole modeling of the valence electron-density distribution, in particular, radial modeling of the M valence shell of the P atom, and deconvolution of the nonspherical density features from anisotropic vibrational smearing.