Knowledge Bank

Line strengths in the 2-0 band of CO have been measured to an estimated accuracy of four per cent for sample pressures between 0.1 mm and 0.5 mm Hg. A spectral slit width of $0.035cm-1$ was used for measurements in this region. The method of equivalent widths was applied to find the line strengths assuming a Doppler line profile. The total band strength was determined from these line strengths by the use of the theory of Herman and $Wallis.1$ The value obtained is $1.86cm-2atm-1$ at $300\circ K$. Line strengths obtained from a second set of measurements with sample pressures between 2 cm and 7 cm Hg will also be presented. These strengths, which are found using the Voigt profile, will be compared with the measurements in the Doppler region and the advantages of using the Doppler line profile for the measurement of line strengths will be discussed.