Table 1.
Vertical excitation energies Evert, oscillator strengths f and the involved transitions for the lowestlying excited states of monomer and stacked dimer obtained with TD-DFT/B3LYP/6-31G(d) in water (PCM). The calculations are performed for a model system with inserted sulfur atoms instead of C(CH3)2 shown in Supporting Figure S6. For the monomer there is only one excitation of importance with an energy of 2.61 eV. In the case of the dimer only the S4 state contributes significantly to the absorption and is clearly blue-shifted compared to the monomer with an energy of 2.8 eV. The corresponding orbitals can be seen in Supporting Information Figure S7.
| State | Transition | Weight (%) | Evert (eV) | F | |
|---|---|---|---|---|---|
| Monomer | S1 | HOMO -> LUMO | 100 | 2.61 | 1.6014 |
| Dimer | S1 | HOMO-1 -> LUMO HOMO -> LUMO+1 |
11 89 |
2.18 | < 5*10-5 |
| S2 | HOMO-1 -> LUMO+1 HOMO -> LUMO |
40 60 |
2.22 | 0.0424 | |
| S3 | HOMO-1 -> LUMO HOMO -> LUMO+1 |
89 11 |
2.43 | < 5*10-5 | |
| S4 | HOMO-1 -> LUMO+1 HOMO -> LUMO |
60 40 |
2.80 | 2.8945 |