and

Simulations have shown that as two metal surfaces approach each other, the surface layers can avalanche together when the rigid interfacial spacing falls below a critical distance. This is accompa-nied by a discontinuous decrease in the adhesive energy. Here we present an examination of this phenomenon for the bcc metals Fe and W using the Equivalent Crystal Theory. In order to identify the circumstances under which avalanche might be inhibited, the effect of loss of registry between the two surfaces is investigated in detail. The avalanche is inhibited when the two surfaces are sufficiently far out of registry and when only a few layers near the surface are al-lowed to relax. As the relaxing slabs get thicker a sharp avalanche reappears. However, as the loss of registry increases the energy released in the avalanche decreases. PACS Numbers: 68.35.-p, 46.30.Pa, 81.40.Pq I