Importance of Surface Morphology in Interstellar H2 Formation
L. Hornekær,1*
A. Baurichter,1
V. V. Petrunin,1
D. Field,2
A. C. Luntz1
Detailed laboratory experiments on the formation of HD from
atom recombination on amorphous solid water films show that
this process is extremely efficient in a temperature range of
8 to 20 kelvin, temperatures relevant for H
2 formation on dust
grain surfaces in the interstellar medium (ISM). The fate of
the 4.5 electron volt recombination energy is highly dependent
on film morphology. These results suggest that grain morphology,
rather than the detailed chemical nature of the grain surface,
is most important in determining the energy content of the H
2 as it is released from the grain into the ISM.
2 Department of Physics and Astronomy, Aarhus University, Denmark.
* To whom correspondence should be addressed. E-mail: hornekaer{at}fysik.sdu.dk
