Hannover 2003 – scientific programme
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MO: Molekülphysik
MO 2: Chemische Reaktionen, Energietransfer
MO 2.6: Talk
Monday, March 24, 2003, 17:45–18:00, B 302
Reactions between ions and H-atoms — •Gheorghe Borodi, Alfonz Luca, and Dieter Gerlich — Department of Physics, Technical University Chemnitz, Germany
An effusive H atom source which can be cooled to low temperatures has been combined with a variable temperature radio-frequency 22-pole ion trap for studying ion-molecular processes at conditions relevant for interstellar chemistry. Experimental tests have been carried out in order to determine the H number density inside the 22-pole trap, the H2 background density, and the degree of dissociation inside the source. For this purpose chemical probing with the reactions CO2+ + H → COH+ + O and CO2+ + H2 → CO2H+ + H has been used. An interesting class of reactions to be studied in the trap experiment is the interaction of H-atoms with hydrocarbons ranging from CH+ to larger CnHm+. In this case one unresolved question is under which conditions an H-atom just "sticksNo-dq, i.e., when the lifetime of the collision complex is so long that emission of radiation leads to its stabilisation. Another important experimentally unknown class of reactions is single or multiple isotope enrichment in collisions of ions such as H3+, CnHm+ or NHn+ with D-atoms.