RNA-like model on the Husimi lattice

We investigate a two-tolerant polymer model on the square Husimi lattice, aiming to describe RNA-like properties. We solve the model in a numerically exact manner, working out the grand-canonical phase diagram. In the dilute solution (single molecule) limit, the system exhibits three qualitatively different behaviors: a swollen (coil) state at high temperatures, a moderately collapsed (molten) state at intermediate temperatures, and an almost fully paired (''native'') state at low temperatures. (c) 2006 Elsevier B.V. All rights reserved.