title: Formaldehyde reactions in dark clouds.
abstract: The low-pressure reactions of formaldehyde (H2CO) with D+, D2+, D3+, and He+ have been studied by the ion cyclotron resonance technique.  These reactions are potential loss processes for formaldehyde in cores of dark interstellar clouds.  The deuterated reactants, which are easier to study experimentally, represent direct analogs for protons.  Rate coefficients and branching ratios of product channels have been measured.  Charge transfer is observed to be the dominant reaction of H2CO with D+, D2+, and He+ ions.  Only the D3+ reaction exhibits a proton transfer channel.  All reactions proceed at rate coefficients near the collision limit.  Proton-deuteron exchange reactions were found to be inefficient processes in the formaldehyde system.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena 91109, USA.
authors.forename: A D
authors.initials: AD
authors.lastname: Sen
authors.forename: V G
authors.initials: VG
authors.lastname: Anicich
authors.forename: S R
authors.initials: SR
authors.lastname: Federman
mesh_terms: D017357:Cyclotrons; D003903:Deuterium / Q000737:chemistry; D005118:Extraterrestrial Environment; D005557:Formaldehyde / Q000737:chemistry*; D006371:Helium / Q000737:chemistry; D011522:Protons
chemical_list: D011522:Protons; D005557:Formaldehyde; D006371:Helium; D003903:Deuterium