Circular dichroism (CD) is the differential absorption of left- and right-handed circularly polarized light. Staring from ADF2010 Hartree-Fock and hybrids can also be used to calculate CD spectra.
EXCITATIONS CDSPECTRUM ANALYTIC VELOCITY End
CDSPECTRUM
If the subkey CDSPECTRUM is included in the key EXCITATIONS the rotatory strengths for the calculated excitations are calculated, in order to simulate Circular Dichroism (CD) spectra [80,81]. Interesting for chiral molecules. This subkey should not be used in case of spin-orbit coupling. For accuracy reasons you should also use the subkey ANALYTIC in the block key EXCITATIONS, otherwise the results may be nonsense.
ANALYTIC
If the subkey ANALYTIC is included the required integrals for the CD spectrum are calculated analytically, instead of numerically. Only used in case of CD spectrum.
Velocity
If the subkey VELOCITY is included ADF calculates the dipole-velocity representation of the oscillator strength. If applicable (use of subkey CDSPECTRUM) the dipole-velocity representation of the rotatory strength is calculated. Default the dipole-length representation of the oscillator strength and rotatory strength is calculated.
