Topology of electron-electron interactions in atoms and molecules. III. Morphology of electron intracule density in two (1)Sigma(+)(g) states of the hydrogen molecule

The differences in electronic structures of two (1)Sigma(g)(+) states of th e hydrogen molecule are vividly reflected in their intracule densities I(r) . The ground-state wave function of H-2 is associated with two distinct top ologies of I(r) (one of which pertains to the united atom limit), whereas n o fewer than 11 unequivalent sets of critical entities are found for I(r) o f the EF state that involves multiple electronic configurations. These sets and the catastrophes that interrelate them, which arise from conflicts bet ween topological features of I(r) pertinent to different configurations, ar e characterized in detail. The usefulness of topological analysis of I(r) i n the detection and characterization of various types of electron correlati on is demonstrated. (C) 1999 American Institute of Physics. [S0021-9606(99) 30132-X].