The evaluation of infrared intensities requires the calculation of the dipole gradients (also known as Atomic Polar Tensors (APTs)). Thus, by combining the calculation of vibrational frequencies with the calculation of dipole gradients, IR intensities will be obtained. Such an input may look like:
**DALTON INPUT
.RUN PROPERTIES
**WAVE FUNCTIONS
.HF
**PROPERTIES
.VIBANA
.DIPGRA
*VIBANA
.ISOTOP
2
1 2 1 1 1
2 1 1 1 1
*END OF INPUT
The keyword .DIPGRA invokes the calculation of the dipole gradients.