Laboratory synthesis of molecular hydrogen on surfaces of astrophysical interest

V Pirronello, C Liu, L Shen, G Vidali�- The Astrophysical Journal, 1997 - iopscience.iop.org
V Pirronello, C Liu, L Shen, G Vidali
The Astrophysical Journal, 1997iopscience.iop.org
We report on the first results of experiments to measure the recombination rate of hydrogen
on surfaces of astrophysical interest. Our measurements give lower values for the
recombination efficiency (sticking probability S times the probability of recombination upon
HH encounter, &ggr;) than model-based estimates. We propose that our results can be
reconciled with average estimates of the recombination rate [(1 &solm0; 2) n H ngv H AS
&ggr;] from astronomical observations, if the actual surface of an average grain is rougher�…
Abstract
We report on the first results of experiments to measure the recombination rate of hydrogen on surfaces of astrophysical interest. Our measurements give lower values for the recombination efficiency (sticking probability S times the probability of recombination upon HH encounter, γ) than model-based estimates. We propose that our results can be reconciled with average estimates of the recombination rate [(1 &solm0; 2) n H n g v H AS γ] from astronomical observations, if the actual surface of an average grain is rougher, and its area bigger, than the one considered in models.
iopscience.iop.org