A multispectrum analysis of the ν2 band of H12C14N: Part I. Intensities, broadening, and shift coefficients


Devi MV, Benner CD, Smith MAH, Rinsland CP, Predoi-Cross A, Sharpe SW, Sams RL, Boulet C, Bouanich JP. A multispectrum analysis of the ν2 band of H12C14N: Part I. Intensities, broadening, and shift coefficients. Journal of Molecular Spectroscopy. 2005;231:66-84.


Absolute intensities, self- and air-broadening coefficients, self- and air-induced shift coefficients and their temperature dependenceshave been determined for lines belonging to the P- and R-branches of the m2 band of H12C14N centered near 712 cm 1. Infraredspectra of HCN in the 14-lm region were obtained at high resolution (0.002–0.008 cm 1) using two different Fourier transformspectrometers (FTS), the McMath-Pierce FTS at the National Solar Observatory on Kitt Peak and the Bruker IFS 120HR FTS atthe Pacific Northwest National Laboratory. Spectra were recorded with 99.8% pure HCN as well as lean mixtures of HCN in air atvarious temperatures ranging between +26 and 60 C. A multispectrum nonlinear least squares technique was used to fit selectedintervals of 36 spectra simultaneously to obtain the line positions, intensities, broadening, and shift parameters. The measured lineintensities were analyzed to determine the vibrational band intensity and the Herman–Wallis coefficients. The measured self-broadeningcoefficients vary between 0.2 and 1.2 cm 1 atm 1 at 296 K, and the air-broadening coefficients range from 0.08 to0.14 cm 1 atm 1 at 296 K. The temperature dependence exponents of self-broadening range from 1.46 to 0.12 while the correspondingexponents for air broadening vary between 0.58 and 0.86. The present measurements are the first known determinationof negative values for the temperature dependence exponents of HCN-broadening coefficients. We were able to support our selfbroadeningmeasurements with appropriate theoretical calculations. Our present measurements are compared, where possible, withprevious measurements for this and other HCN bands, as well as the parameters that are included in the 2000 and 2004 editions ofthe high-resolution transmission (HITRAN) database. 2005 Elsevier Inc. All rights reserved.