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Ionic mechanisms for heterogeneous stratospheric reactions and ultraviolet photoabsorption cross sections for NO 2 + , HNO 3 , AND NO 3 − in sulfuric acid
Author(s) -
Burley Joel D.,
Johnston H. S.
Publication year - 1992
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/92gl01115
Subject(s) - sulfuric acid , nitric acid , chemistry , inorganic chemistry , ionic bonding , catalysis , absorption spectroscopy , ion , absorption (acoustics) , photochemistry , organic chemistry , materials science , physics , quantum mechanics , composite material
We present room temperature photo‐absorption cross sections between 180 and 340 nm for potassium nitrate dissolved in sulfuric acid‐water solutions of 0, 80, and 96% sulfuric acid by mass. Other investigators have obtained ultraviolet absorption spectra for similar solutions above 220 nm, and there is a large literature on the spectra, species, and nitration reactions in sulfuric acid solutions. The predominant nitrogen‐containing species are the nitrate anion (NO 3 − ) in pure water or dilute sulfuric acid solutions, molecular nitric acid (HNO 3 ) in 80% sulfuric acid, and the nitronium ion (NO 2 + ) in 96% sulfuric acid. Upon reviewing the literature involving these species, we consider elementary ionic and molecular reactions in mechanisms of stratospheric heterogeneous catalysis. We formulate a general mechanism for acid catalyzed reactions, with examples that convert inactive HCl and ClNO 3 into photochemically active ClNO 2 , ClNO, Cl 2 , HOCl, and ClO, and we show that reactions forming all of these products are thermodynamically allowed.