The potential energy surface and infrared spectra of the Ar–C2H2 complex

Abstract A new three-dimensional potential energy surface for Ar–C 2 H 2 complex has been generated using the CCSD(T) method. The potential includes explicit dependence on the v 3 stretching coordinate of C 2 H 2 molecule. The basis sets employed are aug-cc-pVQZ for C, H and Ar atoms, with an additional (3 s 3 p 2 d 2 f 1 g) set of midbond functions. The global minimum is located at R = 7.55 a 0 and θ = 59.0 ° geometry with the well depth of −122.02  cm - 1 . The local minimum correspond to the linear Ar–C 2 H 2 configuration at R = 8.75 a 0 with an energy of −114.67  cm - 1 . Bound state energies have been calculated. Calculated microwave and infrared transition frequencies are in good agreement with the experimental data.