CCL: TD-DFT calculations performed for simulation of peptide CD spectrum



 Sent to CCL by: "Debopreeti  Mukherjee" [debopreeti91(-)gmail.com]
 Hello,
 I am trying to simulate the CD spectrum of a peptide using TD-DFT. In my
 peptide, I expect to see an excitonic coupling band arising as a result of
 interactions between two aromatic amino acids (seen from experiment). In
 order to calculate the rotational strength of this band, I need to
 construct a Hamiltonian based on dipole-dipole interactions between the
 aromatic amino acid residues, diagonalize it and then use the eigen vector
 components. I would also need the transition dipole moment values
 corresponding to each aromatic chromophore.
 I ran a TD-DFT calculation (no solvent model, counterpoise for two aromatic
 fragments; according to the paper -
 http://onlinelibrary.wiley.com/doi/10.1002/chir.20792/full)
 and then tried
 to use Matlab to construct the matrices. However, I am confused regarding
 the rotational strength units and the values also seem way off.
 If anyone has done these kind of calculations before, can you please help
 me?
 Thank you so much.
 Regards,
 Debopreeti Mukherjee
 Email id: debopreeti91#,#gmail.com