One of the main challenges in the simulations of many body systems in statistical physics is the problem of generating sufficient coverage of phase space in a reasonable amount of computer time to produce accurate estimates of equilibrium properties. This work is focused on constructing and applying two different nonlocal Monte Carlo techniques which incorporate large-scale changes in a number of degrees of freedom. These methods were then used to study the rotational dynamics of spherical top molecules in He clusters and the problem of conformational sampling of RNA molecules.
