Graphite laser-induced vaporization

Fullerenes were detected for the first time upon laser-induced vaporization of graphite [10]. However, the first preparative method involved the vaporization of graphite by arc discharge (see Fig. 4) [30-33]. Today, the sooting flame from a... 

Limitations to high-temperature materials chemistry research due to the non-availability of suitable container materials have been overcome by laser induced vaporization mass spectrometry (see e.g. Ref. 587). This technique couples laser heating of refractory materials under vacuum with the mass spectrometric analysis of the vapor plume. Hastie et al. [588] have recently investigated the vaporization of graphite by this technique. The investigations by Ohse s group on the laser induced vaporization of fast breeder oxide and carbide fuels should also be mentioned in this context (see Refs. 589, 590 and references quoted therein). 

Vapour-phase Species. The chemical properties of carbon vapour have been reviewed by Skell et al The report describes the preparation of and compositions of the vapour and discusses the chemistry of the constituent species, particularly C, Cg, C3, and C4. Several papers describing detailed aspects of the chemistry of these vapour-phase species have also been published. Chemical reactions of C, Cg, and C3, formed by laser-induced vaporization of either graphite or tantalum carbide, with oxygen, hydrogen, or methane have been studied by means of time-resolved mass spectrometry and gas-phase titrations in an attempt to determine the relative abundances of these three species in the vapour phase (Table 1). The techniques developed and... 

The technique based on laser-induced breakdown coupled to mass detection, which should thus be designated LIB-MS, is better known as laser plasma ionization mass spectrometry (LI-MS). The earliest uses of the laser-mass spectrometry couple were reported in the late 1960s. Early work included the vaporization of graphite and coal for classifying coals, elemental analyses in metals, isotope ratio measurements and pyrolysis [192]. Later work extended these methods to biological samples, the development of the laser microprobe mass spectrometer, the formation of molecular ions from non-voIatile organic salts and the many multi-photon techniques designed for (mainly) molecular analysis [192]. 

Huang and Freiser (132, 133) were able to prepare exohedral metal C60 ions [MC60]+ by direct reaction of the bare metal ions Fe+, Ni+, Co+, Cu+, Rh+, and La+ with Cgo vapor produced from a heated probe. The [MC60]+ ions when subjected to low-energy collision-induced dissociation with argon all produced the Cg0 ion. These results show that the metal ions attach to the outer surface of C60. The exohedral metallofullerene ions differ from the endohedral metallofullerenes produced by laser ablation of metal oxide-graphite mixtures and support the observations of Smalley and co-workers (148) who found that endohedral metallofullerene ions dissociate by loss of C2 units. 

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