THE ROLE OF THE BOND MIDPOINT ELECTRON-DENSITY IN HOMONUCLEAR MOLECULAR-BINDING

Electron density theory is first employed to express the potential energy curve of the H-2+ molecular ion in terms of bond midpoint properties. For heavy homonuclear diatomics, low-order density gradient theory is used, but now for the chemical potential, with a similar conclusion to that for H-2+. Homonuclear clusters of alkali atoms are then treated in some detail. Finally the dissociation of doubly charged clusters is considered, by a study of supermolecular ions (Na-20+)2 and (K20+)2, again using a density gradient expansion in low order. The deviation between the barrier for fission and the Coulomb barrier is linear in the bond midpoint density over a substantial range of fragment separation. (C) 1994 John Wiley & Sons, Inc.