C library for topological study of the electronic charge density.

摘要: The topological study of the electronic charge density is useful to obtain information about kinds bonds (ionic or covalent) and atom charges on a molecule crystal. For this study, it necessary calculate, at every space point, its derivatives values up second order. In work, grid-based method for these calculations described. library, implemented three dimensions, based multidimensional Lagrange interpolation in regular grid; by differentiating resulting polynomial, gradient vector, Hessian matrix Laplacian formulas were obtained point. More complex functions such as Newton–Raphson (to find critical points, where null) Cash–Karp Runge–Kutta (used make paths) programmed. As some crystals, unit cell has angles different from 90°, described library includes linear transformations correct when grid distorted (inclined). Functions also developed handle containing files (grd DMol® program, CUBE Gaussian® program CHGCAR VASP® program). Each one contains data molecular crystal property (such density, spin electrostatic potential, others) three-dimensional (3D) grid. can be adapted any 3D modifying code functions. © 2012 Wiley Periodicals, Inc.