Accurate Kr-CO interaction potential energy surface with vibrational coordinate dependence

The first three-dimensional interaction potential energy surface of the Kr-CO complex is developed using the single and double excitation coupled cluster theory with noniterative treatment of triple excitations [CCSD( T)]. Mixed basis sets, aug-cc-pVQZ for the C and O atom and aug-cc-pVQZ-PP for the Kr atom, with an additional (3s3p2d2f1g) set of midbond functions are used. We first fit the calculated single point energies to an analytic two-dimensional potential model at each of five fixed (r infinity) values. The five model potentials are then used to construct the three-dimensional potential energy surface by interpolating along (r -r(c)) using a fourth-order polynomial. Adopting the vibrationally averaged potential, we calculate the bound states. Compared with the previous work, the present work gives more accurate results along with the experimental data. (c) 2008 Elsevier B. V. All rights reserved.