Superfluid solvation structure of OCS in helium clusters

We make a detailed study of the local solvation structure and energetics of an OCS molecule in clusters of He-4 at finite temperatures. Calculations a re made with the path integral Monte Carlo method, incorporating the exchan ge permutation symmetry of the bosonic He-4 atoms. Analysis of the local ex tent of superfluidity is made with an approximate exchange path estimator d eveloped previously. The sensitivity of the helium solvation structure to t he interaction potential is examined with calculations for two recently pub lished He-OCS potentials, and the vibrational shift of the antisymmetric OC S vibration is estimated from a set of vibrationally adiabatic potentials. We comment on possible effects of molecular rotation on the local solvation structure, and discuss the microscopic two-fluid analysis of the rotationa l spectroscopy of OCS in He-4(N). (C) 2001 American Institute of Physics.