Dissociative Electron Attachment to Hydrogen Halides and their Deuterated Analogs

The swarm‐beam technique has been employed to study the electron‐attachment processes in HX and DX (X = halogen) molecules. Attachment cross sections as a function of electron energy σc(e), corrected for the finite width of the electron beam, are reported for the direct dissociative attachment, i.e., HX(or DX) + e→H (or D) + X−. There is a strong increase in σc(e) in going from HCl to HBr to HI, i.e., with decreasing energy of the dissociative‐attachment peak. The ratio of σc(e) for isotopic species is found to be very nearly equal to the square root of the inverse ratio of the reduced masses of the products. In addition to the direct dissociative electron attachment to HX and DX molecules, a separate attachment process occurs at thermal electron energies.

[1]  D. C. Frost,et al.  Electron Capture Processes in the Hydrogen Halides , 1958 .

[2]  M. S. Freedman,et al.  Correction for Phosphor Backscattering in Electron Scintillation Spectrometry , 1956 .

[3]  W. E. D. B.Sc.  XIV. On the behaviour of electrons amongst the molecules NH3, H2O, and HCl , 1930 .

[4]  H. Neuert,et al.  Negative Ionen bei Dissoziation von HCl und HBr durch Elektronenstoß , 1954 .

[5]  David J. Rose,et al.  Basic Processes of Gaseous Electronics , 1956 .

[6]  L. Christophorou,et al.  Negative-Ion Formation in H_{2}O and D_{2}O , 1967 .

[7]  W. Brittin,et al.  Atomic Collision Processes , 1969 .

[8]  H. A. Barton.  The Ionization of HCl by Electron Impacts , 1927 .

[9]  G. S. Hurst,et al.  Determination of Electron‐Capture Cross Sections with Swarm‐Beam Techniques , 1965 .

[10]  J. Bowe.  Drift Velocity of Electrons in Nitrogen, Helium, Neon, Argon, Krypton, and Xenon , 1960 .

[11]  G. S. Hurst,et al.  An apparatus for measuring electron attachment: results for oxygen in argon. , 1958, Health physics.

[12]  P. W. Reinhardt,et al.  THRESHOLD ELECTRON IMPACT EXCITATION OF ATOMS AND MOLECULES: DETECTION OF TRIPLET AND TEMPORARY NEGATIVE ION STATES. , 1968 .

[13]  E. E. Hanson,et al.  A Mass-Spectrographic Analysis of the Ions Produced in HCl Under Electron Impact , 1936 .

[14]  G. S. Hurst,et al.  Drift Velocities of Electrons in Some Commonly Used Counting Gases , 1957 .

[15]  J. Peacher,et al.  Survival Probability in Dissociative Attachment , 1967 .

[16]  E. W. McDaniel,et al.  Low-Field Mobilities of the Negative Ions in Oxygen, Sulfur Hexafluoride, Sulfur Dioxide, and Hydrogen Chloride , 1959 .

[17]  G. S. Hurst,et al.  Time‐of‐Flight Investigations of Electron Transport in Some Atomic and Molecular Gases , 1967 .

[18]  G. Schulz,et al.  Formation of H - Ions by Electron Impact on H 2 , 1959 .

[19]  R. Curran.  Formation of SF6— by Inelastically Scattered Electrons , 1963 .

[20]  G. Schulz,et al.  ISOTOPE EFFECT IN THE DISSOCIATIVE ATTACHMENT IN H2 AT LOW ENERGY. , 1967 .

[21]  G. S. Hurst,et al.  Swarm Measurement of Cross Sections for Dissociative Electron Capture in Heavy Water, Chlorobenzene, and Bromobenzene , 1964 .

[22]  V. Bailey,et al.  XXX. On the attachment of electrons to the molecules HCl and NH3 , 1929 .

[23]  V. H. Dibeler,et al.  A Survey of Negative Ions in Mass Spectra of Polyatomic Molecules , 1956 .

[24]  R. E. Fox.  Negative Ion Formation in Hydrogen Chloride by Electron Impact , 1957 .

[25]  T. E. Sharp,et al.  Large Isotope Effect in the Formation of H − or D − by Electron Impact on H 2 , HD, and D 2 , 1965 .

[26]  L. Christophorou,et al.  Dissociative Electron Attachment to Molecules , 1968 .

[27]  R. Stephen Berry,et al.  Absorption Spectrum of Gaseous F‐ and Electron Affinities of the Halogen Atoms , 1963 .

[28]  L. Christophorou,et al.  Temporary negative ion resonances in benzene and benzene derivatives , 1966 .

[29]  G. Owen,et al.  Relation between Apparent Shapes of Monoenergetic Conversion Lines and of Continuous β-Spectra in a Magnetic Spectrometer , 1948 .

[30]  L. Megill,et al.  Electron Energy Distribution in Slightly Ionized Air under the Influence of Electric and Magnetic Fields , 1962 .

[31]  G. S. Hurst,et al.  Dissociative Electron Capture by Benzene Derivatives , 1966 .

[32]  N. Bradbury.  Formation of Negative Ions in Gases by Electron Attachment Part I. NH3, CO, NO, HCl and Cl2 , 1934 .

[33]  J. T. Dowell,et al.  Isotope Effects in Dissociative Attachment of Electrons in Methane , 1967 .