Crittenden, Deborah L.Gill, Peter M. W.2015-11-292015-11-290021-9606http://hdl.handle.net/1885/16896The Omega intracule is a three-dimensional function that describes the relative positions, momenta, and directions of motion of pairs of electrons in a system. In this paper, we describe the computation of the Omega intracule for a molecular system whose electronic wave function is expanded in a Gaussian basis set. This is followed by implementation details and numerical tests. Finally, we use the Omega intracules of a number of small systems to illustrate the power of this function to extract simple physical insights from complicated wave functions.We thank the ANU and ARC Grant Nos. DP0664466 and DP0771978 for funding.http://www.sherpa.ac.uk/romeo/issn/0021-9606..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 30/11/15). Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in The Journal of Chemical Physics and may be found at https://doi.org/10.1063/1.2746028Keywords: Computation theory; Electrons; Numerical methods; Wave functions; Electronic wave function; Molecular system; Molecular structure2007-07-0210.1063/1.27460282015-12-08