Potential Energy Surface for the Krypton-Acetylene Complex

1. ""The Potential Energy Surface of $Ne-C_{2}H_{2}$ from Infrared Spectroscopy and Theory'', R.J. Bemish and R.E. Miller, 49th International Symposium on Molecular Spectrocopy. 2. R.J. Bemish, P.A. Block, L.G. Pedersen, Weitao Yand and R.E. Miller, J. Chem. Phys, 99 (1993), 8585-8598.Author Institution:We have obtained a near-infrared spectrum for the $Kr-C_{2}H_{2}$ van der Waals complex. Fitting to a rigid Hamiltonian resulted in a large Dj and a K dependence of both the B and C rotational constants. This suggest that like helium, $neon^{1}$ and $argon-acetylene^{2}$ this complex is not rigid. In the case of the other rare-gas acetylene complexes, it was possible to extract the intermolecular potential using the spectroscopy. As result we fit the $K_{a} = 0 \leftarrow 1, K_{a} = 1 \leftarrow 0$ and $K_{a} = 2 \leftarrow 1$ sub-bands individually, and the rotational constants from the fits were used to find the approximate geometry of the complex which indicated the areas of the potential to which the spectroscopy is sensitive. With this in mind, a HFD potential was constructed using an ab initio respulsive SCF potential and an analytically constructed attractive dispersion potential. With the repulsive surface held fixed, and the attractive surface was adjusted to give agreement with the spectroscopy. The resulting potential energy surface is consistent with the trend of increased rigidity with increased rare-gas size as seen in our previous studies of helium, $neon^{1}$, and argon-$acetylene^{2}.