Broadening of the R(0) and P(2) lines in the 13CO fundamental by helium atoms from 300Â K down to 12Â K: Measurements and comparison with close-coupling calculations

We present measurements of He-broadening parameters for the R(0) and P(2) lines in the fundamental band of 13CO at different temperatures between 12 K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12CO.