Knowledge Bank

We have demonstrated an enhancement of ion signals by about an order of magnitude in the $3\mu m$ region obtained with a hollow-cathode discharge cell. This enabled us to detect the $\nu 1$ fundamental band of $HOCO+$, and we have already reported a preliminary result. Since then more lines have been observed, and now we report a more detailed analysis of the $\nu 1$ band of this ion. The $HOCO+$ ions were generated in a modulated discharge through a flowing gas mixture of $CO2$ (20 mTorr) and $H2$ (250 mTorr). More than 500 lines of both the a-type and b-type transitions were observed in the range of $3300-3400cm-1$. The molecular constants were determined for the ground and excited states. The molecular structure of this ion is similar to that of HNCO. The large centrifugal distortion constants $(\Delta K,\Phi K,---)$ may be an indication of the quasi-linearity of this ion.