Dissociative attachment reactions of electrons with strong acid molecules

Journal Article · Sun Jun 15 00:00:00 EDT 1986 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.450675· OSTI ID:5679282

Adams, N G; Smith, D; Viggiano, A A; Paulson, J F; Henchman, M J

Using the flowing afterglow/Langmuir probe (FALP) technique, we have determined (at variously 300 and 570 K) the dissociative attachment coefficients ..beta.. for the reactions of electrons with the common acids HNO/sub 3/ (producing NO/sup -//sub 2/) and H/sub 2/SO/sub 4/ (HSO/sup -//sub 4/), the superacids FSO/sub 3/H (FSO/sup -//sub 3/), CF/sub 3/SO/sub 3/H (CF/sub 3/SO/sup -//sub 3/), ClSO/sub 3/H (ClSO/sup -//sub 3/,Cl/sup -/), the acid anhydride (CF/sub 3/SO/sub 2/)/sub 2/O (CF/sub 3/SO/sup -//sub 3/), and the halogen halides HBr (Br/sup -/) and HI (I/sup -/). The anions formed in the reactions are those given in the parentheses. The reactions with HF and HCl were investigated, but did not occur at a measurable rate since they are very endothermic. Dissociative attachment is rapid for the common acids, the superacids, and the anhydride, the measured ..beta.. being appreciable fractions of the theoretical maximum ..beta.. for such reactions, ..beta../sub max/. The HI reaction is very fast ( ..beta..approx...beta../sub max/) but the HBr reaction occurs much more slowly because it is significantly endothermic. The data indicate that the extreme acidity of the (Bronsted-type) superacids has its equivalence in the very efficient gas-phase dissociative attachment which these species undergo when reacting with free electrons. The anions of the superacids generated in these reactions, notably FSO/sup -//sub 3/ and CF/sub 3/SO/sup -//sub 3/, are very stable (unreactive) implying exceptionally large electron affinities for the FSO/sub 3/ and CF/sub 3/SO/sub 3/ radicals.

• Research Organization: Department of Space Research, University of Birmingham, Birmingham B15 2TT, England
• OSTI ID: 5679282
• Journal Information: J. Chem. Phys.; (United States), Vol. 84:12
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ELECTRON-MOLECULE COLLISIONS
DISSOCIATION
ELECTRON ATTACHMENT
HYDRIODIC ACID
HYDROBROMIC ACID
HYDROCHLORIC ACID
HYDROFLUORIC ACID
NITRIC ACID
SULFURIC ACID
AFFINITY
ANHYDRIDES
ELECTRONEGATIVITY
INORGANIC ACIDS
COLLISIONS
ELECTRON COLLISIONS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
IODINE COMPOUNDS
MOLECULE COLLISIONS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena