HIGH-RESOLUTION ABSORPTION CROSS-SECTIONS OF CHLORINE NITRATE IN THE NU(2)-BAND REGION AROUND 1292 CM(-1) AT STRATOSPHERIC TEMPERATURES

The infrared absorption spectrum of ClONO2 has been recorded between 500 and 1600 cm-1 at temperatures between 188 K and 222 K and resolutions of up to 0.004 cm-1, The infrared absorption cross sections were determined for the entire nu2 band between 1260 and 1320 cm-1. The cross sections (with 0.025 cm-1 resolution) for the central Q branch absorption maximum at 1292.68 cm-1 are (in 10(-18) cm2 molecule-1) 3.12+/-0.06 at 201 K, 3.45+/-0.15 at 211 K, and 3.31+/-0.06 at 222 K. The influence of resolution on the cross section of the Q branch maximum is small only for resolutions between 0.025 and 0.100 cm-1. In the P and R branches, the cross sections change considerably with increasing resolution. The new absorption cross sections are important for the determination of stratospheric ClONO2 concentrations from atmospheric infrared absorption spectra and for modeling atmospheric transmission in the spectral region around 1292 cm-1.