Showing papers on "Fullerene published in 1989"
IBM1
TL;DR: In this paper, Creasy et al. showed that the neutral and ionic products observed after ablation of polyimide are due to both condensation of the atomic and molecular fragments which form during the ablation laser pulse and nascent polymer fragments.
Abstract: Some of the neutral species which are produced in the laser ablation of polyimide have been characterized using multiphoton ionization/time of flight mass spectrometry. Three different wavelengths (193 nm, 157 nm, and 118 nm) have been used in an attempt to effect soft ionization of the products formed during or after the initial laser ablation of the polymer. Neutral photo-ablation products detected using this scheme range from atomic to high molecular weight species which, depending on the probe wavelength, include pure carbon clusters as well as a broad distribution of heteroatom containing clusters. However, there is virtually no overlap in the mass spectra recorded at each probe wavelength. When probing with 193 nm, marked changes are observed in the mass spectra as a function of the probe flux used. At moderate fluxes, pure carbon clusters (fullerenes) are observed. The identification of a large distribution of species other than pure carbon clusters is in dramatic contrast to the recent observation [W.R. Creasy, J.T. Brenna: Chem. Phys. 126, 453 (1988)] of the positively charged ionic species produced, which are solely carbon clusters. These results suggest that the neutral and ionic products observed after ablation of the polymer are due to both condensation of the atomic and molecular fragments which form during the ablation laser pulse and nascent polymer fragments. Various implications of this result for the unambiguous determination of the true ablation product distribution are discussed.
46 citations
TL;DR: The buckminterfullerene (C60B) is a cage with t-icosahedral symmetry analogous to that of a football as discussed by the authors, with 12 pentagonal and 20 hexagonal faces.
Abstract: It seems remarkable that though carbon has been studied exhaustively for decades a new highly symmetric form, in addition to diamond and graphite, has recently been discovered. The C60B molecule is a cage with t-icosahedral symmetry analogous to that of a football, i.e. 12 pentagonal and 20 hexagonal faces. The molecule, buckminterfullerene, is one of a family highly symmetric fullerence 5/6-face cage species. The spontaneous formation of C60B has led to the discovery of an icosahedral spiral (icospiral) network that explains the structure of carbonaceous particles such as soot. This new topological form solves the spheroidal wrapping problem using planar materials. Curiously giant fullerence structures can be generated as highly symmetric 3D cages by the introduction of only 12 pentagonal defects into a 2D hexagonal sheet network of any size.
21 citations