A multispectrum analysis of the ν1 band of H 12C 14N: Part I. Intensities, self-broadening and self-shift coefficients

Abstract

The infrared spectrum of HCN in the region between 3150 and 3450 cm −1 has been recorded at 0.005 and 0.008 cm −1 resolution using two different Fourier transform spectrometers, the McMath–Pierce Fourier transform spectrometer located at the National Solar Observatory (on Kitt Peak) and the Bruker-120HR Fourier transform spectrometer situated at the Pacific Northwest National Laboratory at Richland, Washington. Room temperature measurements were made of positions, absolute intensities, self-broadening and self-shift coefficients for individual lines belonging to the HCN ν 1 band centered near 3311 cm −1 . These are to our knowledge the first extensive set of self-broadening and self shift measurements in the band. In addition, intensities, self-broadening and self-shift coefficients for several lines of the ν 1+ ν 2 1− ν 2 1 hot band and several intensities for lines in the H 13C 14N and H 12C 15N isotopomers were also determined. A multispectrum nonlinear least-squares fitting algorithm was used to fit the entire spectral region covering the 3200– 3400 cm −1 region of up to 27 spectra simultaneously. The measured line intensities in the ν 1 band were further analyzed to derive the vibrational band intensity and the Herman–Wallis coefficients. Differences in line intensities between 5 and 10% are found with respect to present measurements and the values given in the HITRAN database for m values beyond 25 in the P branch and 5 in the R branch.