Absorption Wavelengths and Bandwidths for Interstellar Searches of C₆₀in the 2400–4100 A Region

Abstract

Low-temp. gas-phase wavelengths and bandwidths for astronomical searches for C60 in the 2400-4100 Å region are detd. from the absorption spectra of C60 in rare gas matrixes at 4 K, coupled with information on the dependence of the vibronic transition frequencies of this fullerene on the Lorentz-Lorenz polarizability parameter of matrixes and solvents. These bandwidths increase from 25 +- 5 cm-1 for the 1 1T1u-1 1Ag band at 4024.0 +- 0.5 Å to 2300 +- 200 cm-1 for the 6 1T1u-1 1Ag band at 2488 +- 8 Å. Spectral observations of astrophys. objects considered to be likely sites of C60 were examd. in the context of the wavelengths and bandwidths of bands of the allowed transitions of C60 which we recommend for searches of this species. No certain pos. assignment of a C60 band was made in the 2400-4100 Å spectral region of these objects. The phys. origin of the obsd. C60 absorption bandwidths is analyzed and discussed in an appendix.