Energy distributions of H{sup +} fragments ejected by fast proton and electron projectiles in collision with H{sub 2}O molecules
- Department of Chemistry, Durham University, South Road, Durham DH1 3LE (United Kingdom)
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro 21945-970, RJ (Brazil)
- Department of Pure and Applied Physics, The Queen's University of Belfast, Belfast BT7 1NN (United Kingdom)
Experimental measurements of the kinetic energy distribution spectra of H{sup +} fragment ions released during radiolysis of water molecules in collision with 20, 50, and 100 keV proton projectiles and 35, 200, 400, and 1000 eV electron projectiles are reported using a pulsed beam and drift tube time-of-flight based velocity measuring technique. The spectra show that H{sup +} fragments carrying a substantial amount of energy are released, some having energies well in excess of 20 eV. The majority of the ions lie within the 0-5 eV energy range with the proton spectra showing an almost constant profile between 1.5 and 5 eV and, below this, increasing gradually with decreasing ejection energy up to the near zero energy value while the electron spectra, in contrast, show a broad maximum between 1 and 3 eV and a pronounced dip around 0.25 eV. Beyond 5 eV, both projectile spectra show a decreasing profile with the electron spectra decreasing far more rapidly than the proton spectra. Our measured spectra thus indicate that major differences are present in the collision dynamics between the proton and the electron projectiles interacting with gas phase water molecules.
- OSTI ID:
- 21313277
- Journal Information:
- Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 80; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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