Orientation effects in H{sub 2} dissociation by He{sup 2+} impact at v{sub P}=1 and 2 a.u

Journal Article · Thu Dec 15 00:00:00 EST 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.72.0· OSTI ID:20786321

Martinez, S; Bernardi, G; Focke, P; Fregenal, D; Suarez, S ^[1]

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1. Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica and Universidad Nacional de Cuyo, 8400 San Carlos de Bariloche, Rio Negro (Argentina)

We have investigated the dependence of two electron processes leading to dissociation on the orientation of the H{sub 2} molecule, by measuring differential cross sections for proton fragment emission in coincidence with the outgoing projectile charge state. Proton energy spectra (4-15 eV) emerging at angles 10 deg. and 90 deg. were obtained for He{sup +} and He{sup 0} charge states from He{sup 2+}+H{sub 2} collisions at E{sub P}=25 and 100 keV/amu (v{sub P}=1 and 2 a.u.). By means of the Franck-Condon approximation we found the contribution to the proton emission from the 2p{pi}{sub u}, 2s{sigma}{sub g}, 2p{sigma}{sub u}, and Coulomb explosion dissociation channels, allowing us to obtain cross sections for double capture, transfer ionization, and transfer excitation processes. Cross sections for double ionization and ionization plus excitation were also obtained from the measured data. The results were discussed on the basis of a two-step model within the independent electron approximation, using a perturbative approach for the single capture process.

• OSTI ID: 20786321
• Journal Information: Physical Review. A, Vol. 72, Issue 6; Other Information: DOI: 10.1103/PhysRevA.72.062722; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
CAPTURE
CATIONS
CHARGE STATES
DIFFERENTIAL CROSS SECTIONS
DISSOCIATION
ELECTRONS
ENERGY SPECTRA
EV RANGE
EXCITATION
EXCITED STATES
HELIUM IONS
HYDROGEN
ION-MOLECULE COLLISIONS
IONIZATION
KEV RANGE
MOLECULES
ORIENTATION
PERTURBATION THEORY
PROTON SPECTRA
PROTONS