Experimental determination of the rate constant for the associative detachment reaction H- + H → H2 + e - At 300 K

Abstract

We have determined the rate constant for the associative detachment reaction of hydride ions with hydrogen atoms (H- + H H2 + e -) at 300 K to be 2.0 (0.6) × 10-9 cm3 s-1, where the error bars represent the total absolute error and include 1σ of the measured values; the error analysis is described in the Appendix. Experiments were carried out in a flowing afterglow instrument using the well-characterized reactions of Cl- + H and OH- + H to calibrate the concentration of hydrogen atoms. Our measurement represents a significant improvement over previous determinations and will reduce uncertainties in cosmological models that rely on this reaction rate constant. © 2009. The American Astronomical Society. All rights reserved.