Vibronic coupling density analysis

Fig. 2 Vibronic coupling density analysis for hydrogen molecule anion (ROHF/6-31G with first derivatives), (a) Vibrational mode, (b) vibronic coupling density rj, (c) electron density difference Ap and (d) potential derivative v. The blue and grey surfaces denote negative and positive densities, respectively...

Clearly all three components have the same on-site densities. What differs are the inter-site or overlap matrix elements. The importance of these inter-site contributions is confirmed by a recent analysis of the vibronic coupling density functional [4]. Parenthetically we note that a function which has the same on-site... 

Density functional theory, direct molecular dynamics, complete active space self-consistent field (CASSCF) technique, non-adiabatic systems, 404-411 Density operator, direct molecular dynamics, adiabatic systems, 375-377 Derivative couplings conical intersections, 569-570 direct molecular dynamics, vibronic coupling, conical intersections, 386-389 Determinantal wave function, electron nuclear dynamics (END), molecular systems, final-state analysis, 342-349 Diabatic representation ... 

The presence of the vibronic states, (< )/, can and generally does modify these simple expectations. This dense manifold of vibronic levels leads to a series of phenomena, which depend, in part, on the densities of levels, p within this set. For instance, the small-molecule limit is characterized by a very low density of levels in this set In this case the non-Bom-Oppenheimer couplings can lead to the observation of perturbations in the spectrum of arising from the vibronic state (,. Such perturbations are associated with the displacement of levels of from their anticipated positions and possibly in the emergence of additional lines in the absorption spectra. This small molecule limit of low-level densities is an ideal case for the assignment and analysis of all spectroscopic lines. 

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