Absolute cross sections for electron-impact ionization and dissociative ionization of the SiF free radical

Journal Article · Fri Jan 15 04:00:00 EST 1988 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.454161· OSTI ID:5713652

Hayes, T R; Wetzel, R C; Baiocchi, F A; Freund, R S

Absolute cross sections for electron-impact ionization of the SiF free radical from threshold to 200 eV are presented for formation of the parent SiF/sup +/ ion and the fragment Si/sup +/ and F/sup +/ ions. A fast beam of SiF is prepared by charge transfer neutralization of an SiF/sup +/ beam. The radicals form in the ground electronic state and predominantly in their ground vibrational state, as shown by agreement of the measured ionization threshold with the ionization potential. The absolute cross section for SiF..-->..SiF/sup +/ at 70 eV is 3.90 +- 0.32 A/sup 2/. The ratio of cross sections for formation of Si/sup +/ to that for SiF/sup +/ at 70 eV is 0.528 +- 0.024; the ratio for formation of F/sup +/ to that of SiF/sup +/ is 0.060 +- 0.008. The observed threshold energy for Si/sup +/ formation indicates the importance of ion pair formation SiF..-->..Si/sup +/+F/sup -/. Breaks in the cross section at 14.3 and 17 eV are assigned as dissociative ionization thresholds.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 5713652
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 88:2; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
CROSS SECTIONS
DISSOCIATION
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
IONIZATION
MOLECULE COLLISIONS
RADICALS
SILICON COMPOUNDS
SILICON FLUORIDES