Computational studies of crystalline H3PO4

Area of Science:

• Quantum chemistry
• Crystallography
• Molecular modeling

Background:

• Accurate molecular structure determination relies on understanding electron density.
• Phosphoric acid (H3PO4) is a key molecule in various chemical processes.
• Modeling electron density requires accounting for both static and dynamic molecular properties.

Purpose of the Study:

• To compute and analyze the electron density distribution of phosphoric acid (H3PO4).
• To simulate X-ray crystal structure factors for static and dynamic molecular models.
• To evaluate pseudoatom multipole modeling techniques for electron density analysis.

Main Methods:

• Calculation of a polarized split-valence wavefunction for H3PO4.
• Simulation of X-ray crystal structure factors using computed wavefunctions.
• Approximation of thermal vibrational effects using anisotropic atomic displacement parameters from neutron diffraction data.
• Testing pseudoatom multipole modeling of the valence electron density.

Main Results:

• The study successfully mapped the molecular electron density distribution of H3PO4.
• Simulated X-ray data were generated for both static and thermally averaged structures.
• Pseudoatom multipole modeling was tested, with a focus on the phosphorus (P) atom's valence shell.
• The ability to deconvolute nonspherical density features from vibrational smearing was demonstrated.

Conclusions:

• The computed electron density provides insights into the electronic structure of H3PO4.
• Simulated X-ray data aid in interpreting experimental crystallographic data.
• The methods allow for a more accurate representation of electron density, separating static and dynamic effects.