Table 5. Exchange of Two Chlorine Atoms for Fluorine on Tetra-ortho-chloro Azobenzene: Vertical Excitation Energies (TD-PBE0/def2-TZVP) and Photoswitch Structures (PBE0-D3/def2-TZVP).
| config. | N=N [Å] | ΦS(Ar1) [deg] | ΦS(Ar2) [deg] | Ψ [deg] | S0 → S1 [nm] | |
|---|---|---|---|---|---|---|
| 2 | trans | 1.236 | 50.8 | 50.8 | 175.3 | 498.5 |
| cis | 1.229 | 60.5 | 60.5 | 5.1 | 474.9 | |
| 8 | trans | 1.243 | 37.3 | 37.3 | 175.7 | 507.6 |
| cis | 1.232 | 58.6 | 58.6 | 8.4 | 452.7 | |
| 8s | trans | 1.241 | 37.6 | 42.8 | 175.5 | 508.0 |
| cis | 1.231 | 56.4 | 66.8 | 6.8 | 452.4 | |
| 9 | trans | 1.246 | 27.7 | 27.7 | 176.7 | 505.5 |
| cis | 1.233 | 59.5 | 59.5 | 8.9 | 440.5 | |
| 10 | trans | 1.242 | 40.5 | 40.5 | 175.1 | 526.9 |
| cis | 1.233 | 60.9 | 60.9 | 6.6 | 450.6 | |
| 11 | trans | 1.248 | 27.0 | 27.0 | 176.7 | 523.2 |
| cis | 1.234 | 57.1 | 57.1 | 9.8 | 463.8 |