The search for low-energy conformers of flexible molecules or clusters of molecules is a central problem in computational chemistry. A geometry optimization of a flexible molecule from a randomly generated initial structure will not usually find the global minimum. Even when the global minimum can be found, the full ensemble is often important for many applications, including, but not limited to, ligand docking, 1 the determination of conformational free energy, and predicting spectra of flexible molecules, particularly for vibrational circular dichroism (VCD) and NMR. Some applications, such as ligand docking, require only that the ensemble is diverse and somewhat representative of the true ensemble in solution.