GMIN is a program that attempts to find the global potential energy minimum for a collection of atoms or molecules using the `basin-hopping' algorithm described by Wales and Doye.[#!walesd97a!#] A constant temperature Monte Carlo (MC) run is performed on the transformed potential energy surface (PES), and the configuration point may either be reset to the latest minimum in the chain or vary freely. The program knows many different empirical potentials and it is straightforward to add new systems. From version 2.2 basin-sampling thermodynamics has been added, and from version 2.3 parallel tempering basin-sampling and basin-hopping have been implemented with MPI.
To start a calculation, you need a file called data in the current directory, along with a file called coords containing the initial coordinates, which can be random. If the SEED keyword is present in data you also need a file called seed containing the seed coordinates. Most output is written to a file called output (the filename can be changed by giving the new name as an argument to the GMIN executable). The file lowest is always created at the end of the run, containing the energies and geometries of the lowest few configurations found in the given run. The geometries are saved in XMakemol xyz format.