ADC(2) NAC and transition dipole moments

Hi there,

I am interested in using ADC(2) implemented in QChem, but I need certain properties to be computed that I am not sure they are implemented: transition dipole moments (I have read they are), the derivative of transition dipole moments and the non-adiabatic coupling. Would it be possible? I haven’t seen any references to NAC and the derivative of the transition dipole moment in the manual. The available version I am working with is qchem 5.3.

Thank you, as always!

Transition dipole moment and oscillator strength for singlet-singlet transitions is printed as part of the normal ADC(2) output. See, for example, sample job named

  Excited state 2 (singlet, A)                                     [converged]
  Term symbol:  2 (1) A                                     R^2 =  4.29237e-10

  Total energy:                                            -75.3913749704 a.u.
  Excitation energy:                                               8.692665 eV

  Osc. strength:                                                      0.005900
  Trans. dip. moment [a.u.]:           [  -0.000000,    0.166445,    0.000000]
  <i|r^2|0> [a.u.]:                    [   0.000000,    0.000000,    0.000000]

  V1^2 = 0.9537, V2^2 = 0.0463

  Important amplitudes:
      occ i     occ j     vir a      vir b          v
     5 (A) A              6 (A) A                -0.6889
     5 (A) A              9 (A) A                -0.0403

Non-adiabatic couplings require ADC(2) force calculations, which are not yet implemented in Q-Chem at the moment.


Thank you very much for your answer!

Is the derivative of the transition dipole moment also available?

Analytic derivatives of ADC(2) energies or properties with respect to nuclear positions are not available. Right now the only way to compute dipole derivatives would be to use the finite difference formula and an external script that generates the displacements, calls Q-Chem to compute transition dipoles, and then evaluates the derivative.