Knowledge Bank

Fourier transform spectra of HCN and $H2CO$ were obtained using the FTS spectrometer at the National Solar Observatory, at Kitt Peak, Arizona. Samples were contained in a 6 m multipass White Cell and the resolution was 0.01 to $0.02cm-1$. 910 lines of three isotopic species of HCN were obtained in the $3300cm-1$ region with an accuracy of approximately $0.0001cm-1$. Spectra were analysed to obtain band origins, rotational constants and $ell$-doubling constants. For $H2CO$, asymmetric rotor parameters and band origins were obtained for $3\nu 2,2\nu 2+\nu 6$ and $\nu 3+\nu 5$ bands. Lines could be fit to a precision of $0.01cm-1$ with partial treatment of perturbations. A 432 m optical path length was used for $H2CO$ measurements.