DETECTION OF CYCLIC CARBON CLUSTERS .1. ISOTOPIC STUDY OF THE NU(E') MODE OF CYCLIC C-6 IN SOLID AR

The cyclic C-6 cluster has been identified for the first time in Fouri er transform infrared spectra of the products from the laser evaporati on of graphite rods trapped in Ar at similar to 10 K. Measurements on spectra produced using both C-12- and C-13-enriched rods combined with the results of new density functional theory calculations performed i n the present work as well as previous calculations by Martin and Tayl or, have resulted in the assignment of the most intense infrared activ e mode, v(4)(e') = 1694.9 cm(-1) of the cyclic C-6 isomer with D-3h sy mmetry. This assignment is based on excellent agreement of the frequen cy, C-13 isotopic shifts, and relative intensities with the theoretica l predictions. (C) 1997 American Institute of Physics.