Cross-section measurements for electron-H$sub 3$$O$$sup +$ recombination

Journal Article · Mon Mar 01 04:00:00 EST 1976 · Phys. Rev., A, v. 13, no. 3, pp. 1000-1011

OSTI ID:4006038

Heppner, R A; Walls, F L; Armstrong, W T; Dunn, G H

Cross sections for electron-H$sub 3$$O$$sup +$ recombination have been measured over an electron energy range of 0.060--1.15 eV by using a trapped-ion technique to contain an ion sample at a temperature of approx. =400 K. The cross section deduced from these measurements can be represented by sigma = 4.6 x 10$sup -18$$E$$sup -2$$.$$sup 9$ cm$sup 2$ for 0.038 < E < or = 0.110 eV; sigma = 4.8 x 10$sup -16$$E$$sup -0$$.$$sup 79$ cm$sup 2$ for 0.110 < E < or = 0.420 eV; and sigma = 7.5 x 10$sup -17$$E$$sup -2$$.$$sup 9$ cm$sup 2$ for E > 0.420 eV. Uncertainties are estimated to be at the +- 50% level. Recombination-rate coefficients were calculated from the deduced cross sections, assuming a Maxwellian electron velocity distribution and trial forms for the cross section below 0.038 eV. Assuming the theoretical E$sup -1$ behavior for the cross section just above zero energy and comparing with the measured rate coefficient of Leu et al. at 540 K, we can deduce consistent cross sections below 0.038 eV to be sigma = 6.0 x 10$sup -15$$E$$sup -1$ cm$sup 2$ for 0 < E < 0.023 eV, and sigma = 4.6 x 10$sup -18$$E$$sup -2$$.$$sup 9$ cm$sup 2$ for 0.023 < E < 0.038 eV. The calculated rate coefficients have temperature dependence T$sup -0$$.$$sup 5$/sube/ at 50 K and T$sup -1$$.$$sup 43$/sube/ at 10$sup 5$ K, and values of the coefficient are in good agreement with all direct measurements. (AIP)

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards, Boulder, Colorado 80302
• NSA Number: NSA-33-027278
• OSTI ID: 4006038
• Journal Information: Phys. Rev., A, v. 13, no. 3, pp. 1000-1011, Journal Name: Phys. Rev., A, v. 13, no. 3, pp. 1000-1011; ISSN PLRAA
• Country of Publication: United States
• Language: English

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RECOMBINATION
VELOCITY