AB-INITIO AND SCALED POTENTIAL-ENERGY SURFACES FOR AR-C2H2 - COMPARISON WITH SCATTERING AND SPECTROSCOPIC EXPERIMENTS

New coupled-cluster ab initio potential energy surfaces (PES's) were d etermined for the interaction of Ar with a rigid acetylene molecule. T hese PES's were in addition modified by scaling the correlation energy . Based on both the original and scaled PES's, close-coupled calculati ons of the total differential scattering cross section were carried ou t. Rovibrational energy levels of the Ar-C2H2 complex were computed va riationally. In addition, we simulated the ir spectra corresponding to excitation of the upper diad of the nu(3)/nu(2)+nu(4)+nu(5) excited m olecular vibrational states. The comparison of all these quantities wi th experiment hows generally good agreement for the several scaled PES 's. In addition, the sensitivity of the PES to the experimental data a re investigated by varying the scaling factor. The original and scaled PES's are also compared with several phenomenological PES's and a pre viously published ab initio PES [F.-M. Tao, S. Drucker, and W. Klemper er, J. Chem. Phys. 102, 7289 (1995)]. (C) 1996 American Institute of P hysics.