Knowledge Bank

Absolute infrared intensities and dipole moment drivatives expressed in atomic polar tensor from are calculated quantum machanically using the 4-31G and $6-31G\ast \ast$ basic sets for the $HCO+$ species and for the isomeric $HOC+$ form, The infrared intensities predicted for these ions are compared with the infrared intensities of other molecules containing carbonyl groups or hydroxyl groups, and the fundamental vibrations of the $HOC+$ ion are found to be quite strong. Charge, charge flux, and overlap contributions to the dipole moment derivatives calculated for the ions show interesting similarities to those for the other isoelectronic species HCN, HNC, and CO.