Breaking limit of atomic distance in an impurity-free monatomic chain

An analytical solution shows that the maximal strain of an impurity-free metallic monatomic chain (MC), or a defect-free nanowire (NW), varies inapparently with mechanical stress but apparently with the separation between the melting point [T_m(K)] and the temperature of operation in terms of exp{[T_m(K)-T]^-1}, where K is the dimension of the NW (for a MC, K = 1.5). Reconciliation of the measured data of Au-MC breaking limit suggests that the discrepancy in measurement arises from thermal and mechanical fluctuations near the T_m of the MC that is (1/4.2)-fold of the bulk value. Findings also favor the mechanism for the high extensibility of a nanograined NW and further indicate that bond unfolding of the lower-coordinated atoms dominates the grain boundary activities, particularly at temperatures approaching surface melting.