Molecular Solids

Solid Cubane:

• The cubane molecule (C₈H₈) is aesthetically appealing due to the highly symmetric cubic shape. Moreover it is the most highly strained, kinetically stable ring system available in quantity, and therefore offers promise in many diverse and interesting practical applications as explosives, high-refractive index lenses, specialty polymers, and fuel additives. While cubane was first synthesized and the room temperature crystal structure was determined in the early 1960's, the high temperature, orientationally disordered structure remained unknown due to experimental difficulties arising from the high vapor pressure and the associated problem of recrystallization. In 1997, we surmounted these challenges and using X-ray and neutron scattering along with various theoretical models, characterized the disordered phase of solid cubane (see Phys. Rev. Lett. 78, 4938, 1997). This work received enormous interest as evidenced by articles in The New York Times (July 15,1997), Science News (52, p. 34, 1997), and Physics Today News Updates (p. 9 August 1997). I have been invited to the University of North Carolina, Chapel Hill, to Ruhr University in Bochum, Germany, and to the European Materials Research Society Meeting in Strasbourg, France to present this work.

  Further details of this research can be found at HERE (opens a new window).

Solid C₆₀:

• C₆₀ molecules adopt several different orientations in the solid state depending on various factors including temperature and intercalated species. In 1993, we combined synthesis and characterization of new C1#1 based materials with theoretical calculations to provide a unified view of orientational ordering of C₆₀ in C₆₀-based solids (see T.Yildirim et al. Phys. Rev. Lett. 71, 1383 (1993)). This work resulted in the widespread realization of the importance of molecular orientational order/disorder phenomena on properties such as superconductivity. I have been received invitations to speak on this subject at many research centers and conferences including the American Physical Society March Meeting in 1994, an international workshop on fullerenes held in Austria 1994. This work has been cited more than 60 times.