Indirect Measurement of Spectral Line Breadth in the Infra-Red

If infra-red absorption by a sample gas is measured at low resolution in the presence and absence of pressure broadening by a non-absorbing gas, information may be obtained concerning breadth and fine structure of individual rotational lines. Data on 590—cm−1 and 1285-cm−1 bands of N2O indicate self-broadening coefficients of about 0.21 and 0.13 cm−1 per atmosphere, respectively. These values may be compared with 0.20 cm−1 per atmosphere obtained by Adel and Barker by direct measurement on the 590-cm−1 band.