INFRARED SPECTRA AND AB INITIO POTENTIAL ENERGY SURFACES FOR ACETYLENE COMPLEXED TO Mg ATOMS AND CLUSTERS

Author Institution: University of North Carolina; Department of Chemistry, University of North CarolinaWe have recently developed a technique to measure high-resolution infrared spectra of molecules attached to metal atoms and clusters. Using this technique, the spectrum of the CH stretching band of the acetylene-Mg van der Waals complex has been measured in superfluid liquid $^{4}He$ droplets. A pure b-type band was observed, indicating that the vibrationally averaged structure of the complex is T-shaped, with the Mg atom binding to the $\pi$-cloud of the acetylene. Spectral bands corresponding to acetylene-$Mg_{n} (n=2-4)$ complexes were also observed. Structural interpretations based on these spectra will be discussed. High level $[CCSD(T)/6-311++G(3df,3pd)]$ ab initio potential energy surfaces were also constructed for these complexes, and structural predictions based on these calculations will be compared with the experimentally determined structures