PNNL

Abstract

Air- and N2 –broadening, and air- and N2-pressure shift coefficients and their temperature dependences have been determined for transitions of the v1 band of H12C14N from 39 laboratory adsorption spectra recorded at 0.005 and 0.008-cm-1 resolutions with two Fourier transform spectrometers. The parameters were retrieved from multispectrum nonlinear least squares fits to the 3200- to 3400-cm-1 region of spectra recorded at temperatures between +26 °C and -60°C. Pure samples of HCN in a 19.95 cm cell and a 0.958 cm cell at room temperature as well as lean mixtures of HCN in N2 or dry air in a coolable cell with a 50 cm absorption path were used in the experiments. Line parameters for N2 broadening were determined by fitting 27 spectra simultaneously while air-broadening parameters were quantified from simultaneous fits to 22 spectra. The absolute intensities, the room-temperature values of self-broadening and self-shift coefficients determined for the v1 band and the v1+v21-v21 hot band transitions for H12C14N and the few intensity measurements for the v1 bands of H13C14N and H12C15N molecules are room-temperature air- to N2-broadening coefficient of lines with assignments between P(29) and R(28) are 0.904 + 0.001. Pressure induced shift coefficients at 296 K are all negative with values between 0 and ~-0.006 cm-1 atm-1 and different rotational dependences in the P- and R-branches. Differences between our results, previous measurements and the parameters that are reported in the 2000 edition of HITRAN (High-Resolution TRANsmission) database are quantified and discussed.