PNNL

Abstract

Abstract The procrystal calculation of the electron densityis a veryrapid procedure that offers a quick way to analyze various bonding properties of a crystal. This studyexplores the extent to which the positions, number, and properties of bond-critical points determined from the procrystal representations of the electron densityfor minerals are similar to those of first-princi- ples ab initio model distributions. The purpose of the studyis to determine the limits imposed upon interpretation of the procrystal electron density. Procrystal calculations of the electron densityfor more than 300 MO bonds in crystals were compared with those previously calculated using CRYSTAL98 and TOPOND software. For everybond-critical point found in the ab initio calculations, an equivalent one was also found in the procrystal model, with similar magnitudes of electron density, and at similar positions along the bonds. The curvatures of the electron densities obtained from the ab initio and the procrystal distributions are highly correlated. It is concluded that the procrystal distributions are capable of providing good estimates of the bonded radii of the atoms and the properties of the electron-density distributions at the bond-critical points. Because the procrystal model is so fast to compute, it is especially useful in addressing the question as to whether a pair of