A Quantum Chemical Topology Software

TopChem2 is a standalone program specifically designed for the topological analysis of the electron density/the electron localization function (ELF)/the Molecular Electrostatic Potential (MEP) functions from three-dimensional cube grids link1 link2 or from wfn gaussian files link3 . The program makes use of a full algorithm enabling to numerically assign the data points grids to basin volumes. It is distributed as binary only, free of charge.

Easily usable in command-line or via a Graphical User Interface written in Python3, automatic and robust.

by J. Pilmé, Laboratoire de Chimie Théorique - Sorbonne Université
contact email:

Basin and Population Analysis

TopChem2 looks for all basins of the gradient scalar field along the descent trajectories from attractor points. The algorithm is similar to the one used by the TopMod program [Computers & chemistry, 23 (6), pp. 597-604, 1999]. Each grid point is assigned to a basin volume, assignment codes are stored in an array.

chgcar ice


System requirements : Linux (GLIBC 2.4 or later), Intel/AMD (x86) processor(s), 64 bit

GUI librairies requirements : tkinter, numpy and matplotlib.

TopChem2 Cube 64-bit: Download


A. Open a linux terminal and extract the files from the tar archive:

             > tar -xvf TopChem2_cube64.tar.gz

B. Change the directory to where the files are located:

             > cd INSTALL_TOPCHEM64

C. Run the bash script installer, it does not require administrative privileges to run:

            >  bash

TopChem2: Julien PILMÉ