34 7 
Reference: JPL Publication 94-26
           Chemical Kinetics and Photochemical Data for Use in Stratospheric
           Modeling
           Evaluation Number 11
           December 15, 1994
           page 117

HO2 + hv -> OH + O

"The absorption cross sections of the hydroperoxyl radical, HO2, in the 200-250
nm region have been measured at troom temperature by Paukert and Johnston
[1239], Hochanadel et al. [682], Cox and Burrows [366], McAdam et al. [1049],
Kurylo et al. [892], Moortgat et al. [1126], Dagayt and Kurylo [396], Lightfoot
and Jemi-Alade [963], who measured the cross sections up to 777K, Crowley et
al. [392]; and Sander et al. [1366] at 227.5 nm.  There are significant
discrepancies in the cross section values, particluarly around 200 nm;  no
definitive explanation of the differences can be offered at present.

Table 9 lists the recommended cross sections, which are taken from the review
by Wallington et al. [1651].  Photolysis of HO2 in the stratosphere and
troposphere is slow and can be neglected, but the UV absorption cross sections
are important in laboratory stydies of reaction kinetics.

Lee [921] has detected O(1D) as a primary photodissociation product at 193 and
at 248 nm, with a quantum yield which is about 15 times larger at the longer
wavelength.  The absolute quantum yield for O(1D) production has not been
reported yet."

Table 9.  Absorption Cross Sections of HO2
=====================================================
  lambda (nm)		1E20 sigma(cm^2)
=====================================================
190			387
200			458
210			454
220			373
230			245
240			135
250			 60