Critic: a new program for the topological analysis of solid-state electron densities

In this paper we introduce critic, a new program for the topological analysis of the electron densities of crystalline solids. Two different versions of the code are provided, one adapted to the LAPW (Linear Augmented Plane Wave) density calculated by the WIEN2k package and the other to the ab initio Perturbed Ion (aiPI) density calculated with the pi7 code. Using the converged ground state densities, critic can locate their critical points, determine atomic basins and integrate properties within them, and generate several graphical representations which include topological atomic basins and primary bundles, contour maps of ρ   and ∇2ρ∇2ρ, vector maps of ∇ρ∇ρ, chemical graphs, etc.Program summaryProgram title: CRITICCatalogue identifier: AECB_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AECB_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GPL, version 3No. of lines in distributed program, including test data, etc.: 1 206 843No. of bytes in distributed program, including test data, etc.: 12 648 065Distribution format: tar.gzProgramming language: FORTRAN 77 and 90Computer: Any computer capable of compiling FortranOperating system: Unix, GNU/LinuxClassification: 7.3Nature of problem: Topological analysis of the electron density in periodic solids.Solution method: The automatic localization of the electron density critical points is based on a recursive partitioning of the Wigner–Seitz cell into tetrahedra followed by a Newton search from significant points on each tetrahedra. Plotting of and integration on the atomic basins is currently based on a new implementation of Keith's promega algorithm.Running time: Variable, depending on the task. From seconds to a few minutes for the localization of critical points. Hours to days for the determination of the atomic basins shape and properties. Times correspond to a typical 2007 PC.