Comment on "Experimental Test of Self-Shielding in Vacuum Ultraviolet Photodissociation of CO"
James R. Lyons,1,*
Roy S. Lewis,2
Robert N. Clayton3
Chakraborty
et al. (Reports, 5 September 2008, p. 1328) demonstrated
very large, wavelength-dependent mass-independent isotopic effects
during carbon monoxide (CO) photodissociation and argued that
self-shielding in CO was not responsible. We suggest that variations
in band oscillator strengths and linewidths among CO isotopologs
are responsible for most of the wavelength dependence observed
and that the reported experiments confirm the importance of
self-shielding during CO photodissociation.
2 Enrico Fermi Institute and Chicago Center for Cosmochemistry, University of Chicago, Chicago, IL 60637, USA.
3 Enrico Fermi Institute and Departments of Chemistry and Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
* To whom correspondence should be addressed. E-mail: jimlyons{at}ucla.edu
