Cold Molecular Beam Electronic Spectrum of C60 and C70.

The electronic spectra of supersonically cooled C60 and C70 have been observed in a molecular beam by two‐photon ionization spectroscopy in the regions 375 to 415 nm and 595 to 640 nm. Clear spectral features are observed in both regions for C60 and in the long wavelength region for C70. Neither molecule is responsible for the diffuse interstellar bands.