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MO: Molekülphysik
MO 17: Poster II
MO 17.20: Poster
Thursday, March 25, 2004, 14:00–16:00, Schellingstr. 3
Characterization of a carbon sublimation source for studying the growth of small carbon cluster ions Cn+. — •Silvio Decker, Igor Savić, Ivo Čermák, and Dieter Gerlich — Department of Physics, Technische Universität Chemnitz, 09126 Chemnitz, Germany
For studying astrochemically relevant collision processes between stored ions (e.g. Cn+ or D3+) and carbon atoms and molecules, a sublimation source has been integrated into an ion trapping apparatus. The sublimation efficiency of two permanently compressed and electrically heated carbon rods has been characterized as a function of the heating power and the resulting operating temperature. The flux of the emitted C, C2 und C3 molecules has been determined via two different methods, electron bombardment and deuteron transfer reactions by analyzing the trap content with a mass spectrometer. Assuming a translational temperature of 3000 K one obtains in the trap which is at a distance of 40 cm, a carbon number density of up to 108 cm−3. A detailed analysis has shown, that a large fraction of the emitted carbon (>70%) condenses already on the rods or in close vicinity. Quantitative analysis of the increase of C4+ product ions allows us to conclude that these ions are growing with rate coefficients larger than 10−11 cm3s−1.