Mass spectrometric and optical spectroscopy studies of clusters and nanoparticles in molecular beams

Title: Mass spectrometric and optical spectroscopy studies of clusters and nano- particles in molecular beams Author: Kamila Moriová Institue: Institute of Physics of Charles University Supervisor: doc. Mgr. Michal Fárník, Ph.D., DSc., J. Heyrovský Institute of Phy- sical Chemistry of the CAS Consultant: RNDr. Václav Profant, Ph.D., Institute of Physics of Charles Uni- versity Abstract: Condensation of ices on the surface of dust grains with activation of these ices by cosmic rays in interstellar medium can lead to formation of complex chemical species. In the present work we primarily examine ammonia clusters, which represent a model system of ice particles. Large ammonia clusters were prepared in molecular beams and pass through a pickup chamber in which me- thanol molecules were captured. After electron ionization of (NH3)N (CH3OH)M clusters, a mass spectrum of ionic fragments was obtained in which fragments with methanol (NH3)n(CH3OH)mH+ predominated over the pure ammonia frag- ments (NH3)nH+ : at least one methanol molecule was present in 75 % fragments. This is in disproportion with the composition of the original neutral precursors, which contain less than 4 % of methanol. Based on the measurement results, we suggest that ammonia is ionized in the first place resulting in the NH+ 4 ion core solvated..