Table 2. Characterization of the Relevant Ground- and Excited-State Geometries of 26DMDP—Energies of S0 and S1 States and Values of Torsion Angles within the Polyenic Chaina.
| structure | E(S0), eV | E(S1), eV | τ1-2-3-4, ° | τ2-3-4-5, ° | τ3-4-5-6, ° | τ4-5-6-7, ° | τ5-6-7-8, ° | τ6-7-8-9, ° | τ7-8-9-10, ° |
|---|---|---|---|---|---|---|---|---|---|
| S0-min (tEtEtEc) | 0 | 4.005 | 180.0 | 180.0 | 180.0 | 179.8 | 179.4 | 178.7 | –27.6 |
| S1-min (tEtEtEc) | 0.629 | 2.967 | 180.0 | 180.0 | 180.0 | 180.0 | 180.0 | 180.0 | 0.0 |
| S1/S0-MECI-C2 | 3.674 | 3.674 | 123.4 | 173.1 | –178.4 | –176.9 | 179.1 | 179.2 | –0.5 |
| S1/S0-MECI-C3 | 3.972 | 3.972 | –117.1 | 110.1 | 178.5 | –170.8 | 176.3 | 179.1 | –6.8 |
| S1/S0-MECI-C4 | 3.628 | 3.628 | 173.4 | 95.8 | –128.6 | –177.2 | 175.0 | 171.1 | –2.3 |
| S1/S0-MECI-C5 | 3.672 | 3.672 | 173.5 | –135.8 | –124.4 | 96.3 | 166.1 | –172.8 | 2.9 |
| S1/S0-MECI-C6 | 3.573 | 3.573 | 179.8 | –173.9 | 177.0 | 105.6 | –123.9 | –124.0 | –2.3 |
| S1/S0-MECI-C7 | 3.546 | 3.546 | 179.1 | –177.3 | –172.7 | 118.4 | 115.6 | –106.4 | –4.4 |
| S1/S0-MECI-C8 | 3.823 | 3.823 | –179.9 | 179.6 | –179.3 | –167.1 | 161.2 | 90.6 | 44.6 |
| S1/S0-MECI-C9 | 3.798 | 3.798 | 180.0 | 179.8 | 179.6 | –178.3 | 175.2 | 171.9 | –59.9 |
| S0-min (tZtEtEc) | 0.194 | 4.168 | 180.0 | 0.0 | 180.0 | 179.9 | 179.3 | 178.7 | –27.6 |
| S0-min (tEtZtEc) | 0.022 | 4.091 | 180.0 | –179.9 | –179.8 | 0.3 | –179.3 | –178.6 | 28.5 |
| S0-min (tEtEtZc) | 0.218 | 4.436 | 180.0 | –179.6 | 179.7 | –179.7 | 160.6 | –10.5 | –44.6 |
a
The energies are quoted relative to the energy of the S0 state at the ground-state equilibrium geometry of the tEtEtEc isomer. They do not include zero-point vibrational energy corrections, as these are not defined for a MECI structure. τ1-2-3-4, τ2-3-4-5, etc., are the successive torsion angles along the polyenic chain.