IR-characterization of a hybrid molecule C60-C3 produced in an argon matrix

We co-deposited carbon vapor molecules together with C-60 in a matrix of solid Ar on a sapphire substrate cooled to temperatures in the range 8-30 K. The carbon vapor molecules were produced by evaporating carbon powder (consisting either of natural carbon C-12 or of 99% enriched C-13) in a Knudsen cell heated to about 2500 K. Under these conditions carbon vapor consists mainly of the species C-3. C-60 was evaporated by a second Knudsen cell filled with C-60 powder and heated to about 500 K. Monitoring the IR spectra of the matrix, we observed the occurrence of new features upon matrix annealing. In particular, we noticed a new and intense absorption feature close to that of C-3. We suspect that this new feature originates from C-60-C-3, i.e. the (2 + 1) cycloaddition product of C-60 and C-3. Using the isotopically substituted form of C-3, namely C-13(3), the observed shift of the IR absorption feature confirms this assumption. (C) 2010 Elsevier Ltd. All rights reserved.