Cross section for single and double ionization of N$sub 2$ and O$sub 2$ molecules by electron impact from threshold up to 170 eV

Journal Article · Sat Nov 01 04:00:00 EST 1975 · J. Chem. Phys., v. 63, no. 9, pp. 3731-3736

OSTI ID:4121893

Mark, T D

Absolute ionization cross sections have been measured for the processes N$sub 2$+e$Yields$$N$$sub 2$$sup +$+2e, N$sub 2$+e$Yields$$N$$sub 2$$sup ++$+3e, O$sub 2$+e$Yields$$O$$sub 2$$sup +$+2e, and O$sub 2$+e$Yields$$O$$sub 2$$sup ++$+3e as a function of electron energy up to 170 eV in a crossed molecule--electron beam apparatus. The ionization cross section curve for producing the singly charged parent ions N$sub 2$$sup +$ and O$sub 2$$sup +$ is found to have at least one inflection of the type first observed by Lawrence for mercury. Using nth root extrapolation the following minimum ionization potentials were derived from the low energy cross section behavior: N$sub 2$$sup +$(X $sup 2$$Sigma$/sub g/ $sup +$) = 15.6 +- 0.1 eV, N$sub 2$$sup ++$$($$sup 3$PI/sub u/) = 42.9 +- 0.3 eV, O$sub 2$$sup +$(X $sup 2$PI/sub g/) = 12.1 +- 0.1 eV, and O$sub 2$$sup ++$(X $sup 1$$Sigma$/sub g/$sup +$) = 35.6 +- 0.3 eV. From distinct breaks in the single ionization cross section curve the following excited states were observed: N$sub 2$$sup +$(B $sup 2$$Sigma$$sup +$/sub u/) = 18.8 +- 0.2 eV, O$sub 2$$sup +$(a $sup 4$PI/sub u/) = 16.0 +- 0.2 eV, and O$sub 2$$sup +$$($$sup 2$$Sigma$/sub g/$sup -$) = 21.0 +- 0.2 eV. In the double ionization cases, a square law was found from threshold up to some 20 eV above threshold. All results are compared with previous measurements if available. (AIP)

• Research Organization: Institut fur Atomphysik der Universitat Innsbruck, A 6020 Innsbruck, Osterreich
• NSA Number: NSA-33-010309
• OSTI ID: 4121893
• Journal Information: J. Chem. Phys., v. 63, no. 9, pp. 3731-3736, Journal Name: J. Chem. Phys., v. 63, no. 9, pp. 3731-3736; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

*ELECTRON-MOLECULE COLLISIONS-- IONIZATION
*NITROGEN-- ELECTRON- MOLECULE COLLISIONS
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Molecular & Chemical Physics--Collision Phenomena
COLLIDING BEAMS
CROSS SECTIONS
ELECTRONS
EV RANGE 10-100
EV RANGE 100-1000
EXCITATION FUNCTIONS
N60400* --Physics (Atomic & Molecular)--Collision Phenomena
NITROGEN IONS
OXYGEN IONS