Knowledge Bank

The infrared spectra of HCN and DCN have been observed from 1900 to $8000cm-1$. The rotational structure has been analyzed for most of the bands yielding values for $\nu 0$, $B\prime -B\prime \prime$, and $B0$. The value of $B0$ compares well with previous measurements. Values for all the anharmonic and interaction terms of the vibrational energy expression have been obtained for both of the molecules. The $\omega e$’s obtained from these terms check the isotope rule.