Note: Melting criterion for soft particle systems in two dimensions

A simple criterion for melting of two-dimensional crystals with soft long-ranged interactions has been proposed. It states that the ratio of the transverse sound velocity of an ideal crystalline lattice to the thermal velocity is a quasi-universal number close to 4.3 at melting. Application of these criteria allows estimating melting lines in a simple yet relatively accurate manner. Two-dimensional weakly screened Yukawa systems are considered as a relevant example