Knowledge Bank

Absorption spectra between $0.8\mu$ and $3.5\mu$ have been obtained at Laboratory A. Cotton with a Fourier Transform $Spectrometer.1$ This apparatus, which can record up to $106$ spectral elements with resolution $\Delta \sigma =5.10-3cm-1$, now operates in vacuum. Thus absolute wave numbers are measured and water vapor lines are $eliminated.2$ Spectra of $H2O$, $N2O$, $CH3Br$, $CH4$ have been recorded at different pressures with an eight meter cell. Examples are given and compared to grating results. As an accuracy check $N2O$ band constants have been computed.