IR INTENSITIES IN CHCL3 AND CDCL3

The integrated intensities of the fundamental ir absorption bands of CHCl3 and CDCl3 have been measured using the pressure-broadening technique. These intensities are interpreted in terms of displacement polar tensors, which give the change of the dipole moment of the molecule due to a set of displacements of their atomic nuclei. The components of these polar tensors for the nuclei of both molecules have been calculated for all the possible combinations of the signs of the dipole moment derivatives with respect to the normal coordinates. By comparing the results for both molecules and for CHF3 and SiHCl3, the most satisfactory choice of signs has been decided. Calculations of integrated intensities from recorded spectra and of displacement polar tensors from these intensities, have been carried out in a 7070-IBM computer, for which several programmes have been written. © 1969.