Figure 3.

Analysis of k_RISC in DABNA. (a) Contributions by vibrational modes with strong resonance enhancements, namely ν₁₀₆, ν₁₁₆, and ν₁₁₈. The ΔE_ST values at which become maxima are marked as vertical lines. (b) Contributions by each vibrational mode to k_SV at the vertically marked energies in a. The contribution is further partitioned into spin-manifold components according to eq 4. (c) Convergence profiles of the sum-over-electronic-states expansion for each mode in the triplet manifold. Similar profiles in the singlet manifold are provided in Figure S1. Here, the excited state with a dominant contribution (T₃) can be easily identified as marked with gray spheres. Convergence was reached with 20 excited states as denoted with dashed lines and stars. The T₁ energy was used as the zero energy reference. (d) Natural transition orbital pairs from the ω*B97X calculations at the S₁ geometry. Hole (red) and particle (blue) wave functions are represented by frontier orbitals with the largest weights, shown in parentheses. The S₁ and the T₁ energies are from the SCS-CC2 level calculations. (e) Nonadiabatic T₁–T₃ and S₁–S₆ coupling vectors responsible for RISC.