Open AccessDetermination of intramolecular isotope distribution of ozone by oxidation reaction with silver metal
Author(s) -
Bhattacharya S. K.,
Pandey Antra,
Savarino J.
Publication year - 2008
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jd008309
Subject(s) - ozone , analytical chemistry (journal) , photodissociation , oxygen , chemistry , intramolecular force , metal , isotope , oxide , kinetic isotope effect , environmental chemistry , photochemistry , stereochemistry , organic chemistry , physics , deuterium , quantum mechanics
The intramolecular distribution of 17 O in ozone was determined by a new technique using oxidation reaction of ozone with silver and measuring the isotope ratios 18 O/ 16 O and 17 O/ 16 O of silver oxide, ozone and leftover oxygen. These data along with known 18 O distribution in ozone given by Janssen (2005) in terms of r 50 = [ 16 O 16 O 18 O]/[ 16 O 18 O 16 O] allow us to determine r 49 = [ 16 O 16 O 17 O]/[ 16 O 17 O 16 O]. It is seen that r 49 values increase from 2.030 to 2.145 with increase of bulk 17 O enrichment in ozone from 11.7‰ to 106.3‰ (controlled by varying temperature and pressure during ozone formation) just as r 50 values increase from 1.922 to 2.089 with increase in bulk 18 O enrichment over the same range. Over bulk enrichment level up to ∼100‰ the r 49 values are higher than r 50 values by 0.075 ± 0.026. The difference is small but significant since it corresponds to a large change in enrichment values of the asymmetric and symmetric types of 17 O 16 O 2 and 18 O 16 O 2 relative to a hypothetical ozone standard with statistical isotope distribution. The difference reduces with increase in bulk ozone enrichment. We do not find any significant variation in r values between ozone samples made by Tesla discharge and by UV photolysis of oxygen. Additionally, for ozone samples with negligible enrichment, the symmetrical isotopomers have relatively more heavy isotopes than the asymmetrical ones consistent with their bond strength difference. Atmospheric implications of the results are briefly discussed.