  We have performed Diffusion Quantum Monte Carlo simulations of Li clusters
showing that Resonating-Valence-Bond (RVB) pairing correlations between
electrons provide a substantial contribution to the cohesive energy. The RVB
effects are identified in terms of electron transfers from s- to p-like
character, constituting a possible explanation for the breakdown of the Fermi
liquid picture observed in recent high resolution Compton scattering
experiments for bulk Li.
