Molecular geometry and vibrational frequencies by parallel sampling

Quantum Monte Carlo is an efficient technique for finding the ground-state energy and related properties of small molecules. A major challenge remains in accurate determination of a molecule's geometry, i.e. the optimal location of its individual nuclei and the frequencies of their vibration. The aim of this article is to describe a simple technique to accurately establish such properties. This is achieved by varying the trial function to accommodate changing geometry, thereby removing a source of rather unpleasant singularities which arise when the trial function is fixed (the traditional approach).