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Abstract: Lorentz pressure-broadening and pressure-induced shift coefficients along with their temperature dependences have been determined for over forty P- and R-branch transitions in the fundamental band of 12C16O broadened with helium. A total of nineteen spectra recorded at various temperatures (+24 to −194°C) in the 2010–2260cm−1 spectral region were analyzed simultaneously using a multispectrum nonlinear least squares fitting technique. The spectra were recorded with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on Kitt Peak. Present results are compared with similar measurements reported recently. [Copyright &y& Elsevier]

Line intensities of the three lowest fundamentals of the 12CH3D Triad are modeled with an RMS of 3.2% using over 2100 observed values retrieved by multispectrum fitting of enriched sample spectra recorded with two Fourier transform spectrometers. The band strengths of the Triad in units of 10-18 cm-1/(molecule cm-2) at 296 K are, respectively, 2.33 for ν6 (E) at 1161 cm-1, 1.75 for ν3 (A1) at 1307 cm-1 and 0.571 for ν5 (E) at 1472 cm-1. The total calculated absorption arising from 12CH3D Triad fundamentals is 4.65×10-18 cm-1/(molecule cm-2) at 296 K. In addition, some 740 intensities of nine hotbands are fitted to 8.1%; most of the hotband measurements belong to 2ν6-ν6 and ν3+ν6-ν3 near 1160 cm-1, 2ν3-ν3 near 1290 cm-1 and ν3+ν6-ν6 near 1304 cm-1. The other observed hotbands are ν5+ν6-ν6, 2ν5-ν5, ν5+ν6-ν5, ν3+ν5-ν3, and ν3+ν5-ν5. [Copyright &y& Elsevier]

A variable-temperature single-pass absorption gas cell with an optical pathlength of 147.5 cm was designed and built for spectroscopic measurements of gases of atmospheric interest. The cell is optically matched to a Bomem DA8.3 Fourier transform spectrometer. A heating/cooling system enveloping the cell, used together with a Neslab ULT-80 thermal bath, allows spectroscopic studies of gas samples at temperatures ranging from 205 to 350 K and at pressures up to 1 atm. Tests of the optical, thermal, and vacuum operation of the system were performed. Spectra of the 3←0 vibrational–rotational band of carbon monoxide were recorded from 225 to 348 K and used to determine the rotational gas temperatures. These results were compared with values obtained using thermocouples, in order to assess the thermal performance of the new system. A second temperature-controlled cell 25-cm long, able to withstand pressures up to 30 atm, was also used to record CO spectra. We have recorded high-resolution FTIR spectra of CO and CO perturbed by N2 at temperatures from 295 to 348 K. The spectra were analyzed to determine pressure broadening and pressure-induced shift coefficients, along with their temperature dependence for several transitions in the second overtone band of CO. The results, especially for self-broadening, are in excellent agreement with other recent measurements reported in the literature. [Copyright &y& Elsevier]