Chemical reactions studied at ultra-low temperature in liquid helium clusters
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the University of Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany)
Low-temperature reaction rates are important ingredients for astrophysical reaction networks modeling the formation of interstellar matter in molecular clouds. Unfortunately, such data is difficult to obtain by experimental means. In an attempt to study low-temperature reactions of astrophysical interest, we have investigated relevant reactions at ultralow temperature in liquid helium droplets. Being prepared by supersonic expansion of helium gas at high pressure through a nozzle into a vacuum, large helium clusters in the form of liquid droplets constitute nano-sized reaction vessels for the study of chemical reactions at ultra-low temperature. If the normal isotope {sup 4}He is used, the helium droplets are superfluid and characterized by a constant temperature of 0.37 K. Here we present results obtained for Mg, Al, and Si reacting with O{sub 2}. Mass spectrometry was employed to characterize the reaction products. As it may be difficult to distinguish between reactions occurring in the helium droplets before they are ionized and ion-molecule reactions taking place after the ionization, additional techniques were applied to ensure that the reactions actually occurred in the helium droplets. This information was provided by measuring the chemiluminescence light emitted by the products, the evaporation of helium atoms by the release of the reaction heat, or by laser-spectroscopic identification of the reactants and products.
- OSTI ID:
- 22075841
- Journal Information:
- AIP Conference Proceedings, Vol. 1501, Issue 1; Conference: 28. international symposium on rarefied gas dynamics 2012, Zaragoza (Spain), 9-13 Jul 2012; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
ATOM-MOLECULE COLLISIONS
ATOMS
CHEMICAL REACTIONS
CHEMILUMINESCENCE
DROPLETS
HELIUM
HELIUM 4
IONIZATION
ION-MOLECULE COLLISIONS
MAGNESIUM
MASS SPECTRA
MASS SPECTROSCOPY
MOLECULAR CLUSTERS
OXYGEN
REACTION KINETICS
SILICON
SUPERFLUIDITY
TEMPERATURE DEPENDENCE