A three-dimensional potential energy surface and infrared spectra for the Kr–OCS van der Waals complex

The first three-dimensional potential energy surface (PES) of the Kr–OCS complex is developed at the CCSD(T) level with a large basis set plus midpoint bond functions. The potential includes explicit dependence on the v3 antisymmetric stretching coordinate of the OCS molecule. Two vibrationally adiabatic potentials with the OCS molecule at both the ground and the first vibrational v3 excited states are generated. The resulting potentials provide a good representation of the experimental infrared data: for 66 infrared transitions the root-mean-square discrepancy is about 0.011 cm−1. The calculated infrared band origin shift, bending ground frequency, and molecular constants associated with the v3 fundamental of OCS are all in better agreement with the experimental counterparts.