Velocity distributions and photodissociation of neutral C60 and C70 clusters

Purified samples of C60 and C70 are synthesized according to recently published procedures. Desorption with 308 nm laser light from solid C60 and C70 samples is used as a neutral cluster source to study the ionization and concurrent fragmentation in the gas phase by interaction with intense laser radiation. According to a well‐known classification scheme, the ionization/fragmentation behavior of C60 and C70 clusters is clearly identified as of class A type. Also, the laser desorption process itself has been investigated by measuring the velocity distributions of laser desorbed neutral C60 and C70 clusters. Good agreement of the experimental data with a Maxwell‐Boltzmann distribution is found. We conclude that at the applied laser fluences, C60 and C70 clusters are desorbed by evaporation induced by the incident radiation, providing no fragmentation in the desorption process.

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