DETERMINATION OF THE H2O-NO2-NO2+ BOND STRENGTHS AND THE PROTON AFFINITIES OF NITRIC-ACID AND METHYL NITRATE( AND CH3O(H))

The binding energies of water and methanol to NO2+ have been measured to be 14.8 +/- 2.3 and 19.2 +/- 2.3 kcal/mol, respectively, using ener gy-resolved collision-induced dissociation of H2O-NO2+ and CH3O(H)-NO2 + in a flowing afterglow triple quadrupole apparatus. These values are used with literature thermochemistry to derive proton affinities for nitric acid and methyl nitrate: PA(HONO2) = 177.7 +/- 2.3 kcal/mol and PA(CH3ONO2) = 175.0 +/- 2.5 kcal/mol. These results are in good agree ment with recent calculations by Lee and Rice, but only the methyl nit rate result is in agreement with experimental results of Cacace and co workers.