A novel merged beams apparatus to study anion-neutral reactions

Abstract

We have developed a novel laboratory instrument for studying gas phase, anion-neutral chemistry. To the best of our knowledge, this is the first such apparatus which uses fast merged beams to investigate anion-neutral chemical reactions. As proof-of-principle we have detected the associative detachment reaction H−+H→H2+e−. Here we describe the apparatus in detail and discuss related technical and experimental issues.

Associative detachment of H−+ H→H2+eMiller1, Bruhns2, Eliášek3 et al. 2011Phys. Rev. ASelf Cite351360View full textAdd to dashboardCite

“…We have modified the experimental methods used in [3,5,6] to measure reaction (1) up to E r ≤ 4.83 eV. Additionally, we have performed several modifications to better control potential systematic errors.…”

“…This merged beams approach allows us to reach collision energies on the order of a few meV, limited only by the alignment of the beams, the spread in collision angles between the two beams, and the energy spread of each beam. We used geometrical simulations [3,5,6] to determine the average collision energy E r versus U f , taking into account the spreads in beam energies and angles. After the gas cell, the neutrals and resulting ions enter the analyzer region involving two double-focusing, electrostatic cylindrical deflectors in series [10] and a channel electron multiplier (CEM).…”

Isotope effect for associative detachment:H(D)−+H(D)→H2(Miller1, Bruhns2, Čı́žek3 et al. 2012Phys. Rev. ASelf Cite292240View full textAdd to dashboardCite

“…Our experimental and theoretical approaches have been previously described in detail in [1][2][3][4]16]. Here we give only brief overviews of each.…”

PAHs and the Chemistry of the ISM

“…In addition, two new experimental methods enable the characterization of ion chemistry involving atomic reactants at low energies. These include the innovative atomic beam 22-pole ion trap (Gerlich & Smith 2006;Luca et al 2006), which can approach temperatures as low as 10 K, and the novel merged beam apparatus at the Columbia Astrophysics Laboratory (Bruhns et al 2010).…”