Knowledge Bank

The nitrogen-, carbon dioxide-, and self-broadened halfwidth have been measured for the sP(1,0) line of the $\nu 2$ band of ammonia at $300\circ K$ and $400\circ K$ using a tunable diode laser spectrometer built at Perkin-Elmer Corporaion. Preliminary results for the Lorentz half widths in these three cases at $300\circ K$ were found to be 0.12, 0.23, and $0.44cm-1$ $atm-1$ respectively Assuming a power law dependence of half width on temperature given by $\gamma (T)=\gamma (To)(T/To)n$, the preliminary value of the index n is found to be close to 0.75 in each case. The integrated line intensity in each case was used as a self-consistency check. Its preliminary value for the Doppler case was $3.0cm-2$ $atm-1$. The use of a tunable diode laser spectrometer for these measurement is critically reviewed with respect to the instrumental line profile, the least squares analysis techniques, wave-length scale linearity, wavelength scale relative calibration, and line intensity measurement.