Reaction channels in a plasma reactor-laser vaporization source. Formation of carbon clusters and metal-carbon clusters

Abstract

Two reaction channels have been found when light hydrocarbon gases are introduced into the carrier gas of a plasma reactor coupled with a laser vaporization source employing a metal rod assembly. These involve dehydrogenation to produce pure carbon clusters, and formation of metal-carbon bonds to produce metal-carbon clusters, MmCn−. Using a time-of-flight mass spectrometer system coupled with a laser vaporization plasma source, experiments are conducted to investigate the optimum conditions for selecting the desired reaction channels. Varying the conditions of the plasma reactor results in a striking difference in the species produced as evidenced in the recorded mass spectra. That is, either a pure carbon cluster series or a metal-carbon cluster series MmCn+ (with a magic peak at MgC12+) is obtained. These studies demonstrate an alternative way to produce beams of carbon clusters, and also have led to the further development of a method useful for investigating the properties of metal-carbon clusters.