IR-characterization of a hybrid molecule C 60–C 3 produced in an argon matrix

Abstract

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 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 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 13C 3, the observed shift of the IR absorption feature confirms this assumption.