Ab initio LCAO Calculations of Small Helium Clusters

Abstract

He clusters represent an anomalous case in the field of nanosized structures owing to the extremely low value of the temperature of the liquid phase in bulk helium. The weak dissipative forces which hold these clusters together offer a severe benchmark for calculations of all types. Owing to the interest in phenomena of superfluidity and superconductivity, calculation methods, optimized from either the computational or the mathematical point of view, are the object of very intensive efforts. In this study we report calculations of the structure and energetics of small He clusters obtained by using a LCAO method of the ab initio type with simple trial functions of the gaussian type. The results indicate that the cluster structure is correctly predicted, though deep spurious minima in the energy potential surface are also found.