Using recently measured rates for isotopic variants of the ozone formation
reaction O + O-2 + M, we derive expressions for the enrichment of symmetric
and asymmetric O-50(3) and O-49(3) in stratospheric ozone and calculate to
tal enrichments of 123 parts per thousand and 107 parts per thousand for O-
50(3) and O-49(3), respectively. We compare the calculations with measureme
nts made with the Smithsonian Astrophysical Observatory far-infrared spectr
ometer during seven balloon flights Which took place between 1989 and 1997,
We find that the calculations are in reasonable agreement with the average
observed enrichments of 102+/-43 parts per thousand and 73+/-60 parts per
thousand for O-50(3) and O-49(3), respectively, where the errors indicate t
he estimated accuracy; we also find that our measurements are in agreement
with other recent stratospheric and tropospheric measurements. Using our me
asurements of the enrichment of the asymmetric and symmetric forms of O-50(
3) and O-49(3), We estimate branching ratios of 0.43+/-0.03 and 0.46+/-0.06
for production of the symmetric isotopomer by the reaction of O-16 with O-
34(2) and O-33(2), respectively.