Solid C 60 – How we Found It

In May of 1990, crystals of a new form of carbon were observed crystallizing from a solution of the newly-produced macroscopic quantities of fullerene molecules. This discovery followed many years of work we had done in producing and measuring the optical properties of small particles of graphitic carbon, a work which was aimed, in part, at a better understanding of the various spectral features of interstellar material. Among three distinctly different types of carbon particulates, distinguished by their differing ultraviolet and Raman spectra, was one that later proved to contain macroscopic quantities of C 60 and C 70 . Evidence for fullerenes came from mass spectra, infrared spectra, and X-ray and electron diffraction. More, recent experiments with our collaborators have included scanning tunneling microscopy and gas phase emission spectroscopy in the infrared. At the moment, there is no obvious connection with interstellar spectral features.