Simulating Vibrationally Resolved Electronic and Raman Spectra

A built-in module for computing vibrational progressions affords calculations of vibrationally resolved one-photon absorption (OPA), one-photon emission (OPE), and resonance Raman spectra (RRS):

  • Effective algorithm reduces computational costs by recasting sum-over-state expressions into the time-domain, thus avoiding explicit calculation of individual excited states.

  • Different levels of theoretical treatment are implemented:

    • Franck-Condon (FC): includes only the zero-order term of the transition dipole moment.

    • Franck-Condon-Herzberg-Teller (FCHT): includes the zero- and first-order terms of the transition dipole moment.

    • Vertical gradient (VG): the excited state potential energy surface is approximated by a shift to the ground-state surface.

    • Duschinsky rotation: includes mode mixing effect.

Calculated FC (blue) and FCHT (red) absorption spectra of D\(_0\rightarrow\)D\(_3\) transition for phenoxyl radical

Calculated FC (blue) and FCHT (red) emission spectra of D\(_1\rightarrow\)D\(_0\) transition for benzyl radical