IR-characterization of a hybrid molecule C60–C3 produced in an argon matrix Original Research Article

We co-deposited carbon vapor molecules together with C60 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 12C or of 99% enriched 13C) in a Knudsen cell heated to about 2500 K. Under these conditions carbon vapor consists mainly of the species C3. C60 was evaporated by a second Knudsen cell filled with C60 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 C3. We suspect that this new feature originates from C60–C3, i.e. the (2 + 1) cycloaddition product of C60 and C3. Using the isotopically substituted form of C3, namely 13C3, the observed shift of the IR absorption feature confirms this assumption.