PAULING RESONATING VALENCE-BOND THEORY OF METALS - SOME STUDIES ON LITHIUM CLUSTERS

We report for the first time fully ab initio valence bond (VB) calcula tions with explicit use of the unsynchronized resonance structures int roduced by Pauling [1]. We show that resonance involving these structu res largely determines the stability and conformation of the Li-4 clus ter and plays a central role in a VB explanation of the 3-center bonds in planar alkali clusters. The theory can make qualitative prediction s on the behaviour of general metallic clusters, and can relate stabil ity and conformation to electronic structure, thus indicating the orig in of magic numbers. This first ab initio test of Pauling's resonating VB theory confirms the importance of the metallic orbital and the cov alent character of the metal-metal bond.