Knowledge Bank

The absorption near the fundamental C-H stretching region of HCN ($3311cm-1)$ has been measured at a temperature of $1100\circ K$. Rotational levels up to $J=65$ have been observed and more accurate values have been determined for the centrifugal distortion constants, especially the $HJ$ term. Many ``hot’’ band transitions have been identified giving information on the term values for states which have not been observed in room temperature spectra. Some of the spectra were taken with new instrumentation which digitizes the output of the detector and records the digitized spectral data on magnetic tape. The tape is then processed by a computer which reduces the data to a table of line intensities and wave numbers. This climinates the laborious task of measuring charts and has the potential for giving more precise measurements.