Rate coefficients for D(1s)+H+ ⇆ D++H(1s) charge transfer and some astrophysical implications

We have calculated the rate coefficients for D(1s) + H+ reversible arrow D+ +H(1s) using recently published theoretical cross sections. We present results for temperatures T from 1 K up to 2x10(5) K and provide fits to our data for use in plasma modeling. Our calculations are in good agreement with previously published rate coefficients for 25less than or equal toTless than or equal to300 K, which covers most of the limited range for which those results were given. Our new rate coefficients for Tgreater than or similar to100 K are significantly larger than the values most commonly used for modeling the chemistry of the early universe and of molecular clouds. This may have important implications for the predicted HD abundance in these environments. Using our results, we have modeled the ionization balance in high-redshift QSO absorbers. We find that the new rate coefficients decrease the inferred D/H ratio by less than or similar to0.4%. This is a factor of greater than or similar to25 smaller than the current greater than or similar to10% uncertainties in QSO absorber D/H measurements.