THE H-3(- A 2-PARTICLE DENSITY STUDY OF ELECTRON CORRELATION() MOLECULE ION )

Changes in the one- and two-particle densities arising from Coulomb co rrelation have been examined, in detail, for the ground state of H-3(). This electron deficient system was described in its equilateral tri angular conformation by a wave function which recovered approximately 99% of the correlation energy. Contour diagrams are presented for dens ities evaluated in the molecular plane and also in a plane perpendicul ar to the molecule. For the two-particle distribution, correlation eff ects are highlighted in different regions of the system by considering a series of fixed positions for a ''test'' or ''reference'' electron. In addition, for each location of the test particle, planar Coulomb h oles are determined which emphasize the relative importance of the rad ial and angular components of correlation. Contrary to an earlier stud y, it is demonstrated that Coulomb correlation reduces the density wit hin the H-3(+) nuclear triangle. The present findings are compared wit h a similar analysis for the H-2 molecule in position (real) space, al ready reported.