15min:

CHARLES CHACKERIAN, NASA Ames Research Center and SETI Institute, Mail Stop 245-5, Moffett Field, CA 94035-1000; STEVEN W. SHARPE, THOMAS A. BLAKE, ROBERT L. SAMS, Pacific Northwest National Laboratory, P. O. Box 999, Mail Stop K8-88, 3020 Q Avenue, Richland, WA 99352 (PNNL is operated for the US Department of Energy by the Battelle Memorial Institute under contract DE-AC06-76RLO 1830).

Moderate-resolution spectra (0.112 cm^-1) (MRS) and high-resolution spectra (0.002-0.003 cm^-1) (HRS) of anhydrous nitric acid have been recorded between about 820 cm^-1 and 3600 cm^-1. The MRS were recorded using a Bruker IFS 66V FTIR for at least five pressure burdens at each of three temperatures (278, 298, 323 K) in a temperature regulated cell with BaF₂ windows. Nominal pathlength was 20 cm. The static fills of anhydrous nitric acid samples were back filled with nitrogen to a total pressure of 760 \pm 5 Torr. Small absorbances from H₂O, CO₂, NO, NO₂ and N₂O were accounted for and subtracted from the spectra. The corrected spectra were used to obtain integrated band absorption coefficients as well as a compilation of absorption coefficients tabulated at 0.056 cm^-1 intervals. Within an experimental error of about two percent, the integrated band intensities are independent of temperature and in good agreement with results obtained by Giver et al. HRS of nitric acid were recorded with a Bruker IFS 120HR FTIR using a flow of neat anhydrous nitric acid through a temperature regulated (296 K) cell with a nominal pathlength of 10 cm and BaF₂ windows. At least four pressure burdens were measured for each spectral region. Progress will be reported on the line by line analysis of the HRS for intensities in the 845-945 cm^-1 ( ₅, 2 ₉), 1270-1370 cm^-1 ( ₃, ₄), and 1660-1760 cm^-1 ( ₂) spectral regions.