15min:
INFRARED ABSORPTION SPECTROSCOPY OF SMALL CARBON CLUSTER cdot WATER COMPLEXES ISOLATED IN SOLID Ar.

MARK DIBBEN, JAN SZCZEPANSKI AND MARTIN VALA, Department of Chemistry and The Center for Chemical Physics, Gainesville, FL 32611.

The 1:1 complexes between Cn (n \leq 13) carbon clusters and the H2O molecule formed in Ar matrices at 12K have been investigated experimentally. In addition, IR absorption bands found with higher energy than the Cn cdot H2O C-C stretching bands have been assigned to 1:2 complexes with the general structure H2O cdot Cn cdot H2O, rather than Cn cdot (H2O)2. The proposed structure is supported by geometry optimization and harmonic frequencies calculated at B3LYP/6-31G** level for the Cn cdot H2O, H2O cdot Cn cdot H2O and Cn cdot (H2O)2 systems. In particular, the 13C-labeled experimental spectra for 12/13C5 cdot H2O and 12/13C6 cdot H2O complexes will be presented and compared to the calculated ones at the B3LYP/6-31G** level. The CnO and C2H2 final photoproducts observed after UV matrix photolysis will be discussed within the context of possible photo-production of these species in interstellar space.