Reorganization energies (kcal mole−1) of symmetric (λsym) and asymmetric (λasym) cyanine systems and their relative magnitudes (λasym/λsym).
| λ sym | λ asym | λ asym /λsym | |
|---|---|---|---|
| Cy5 | 6.44 | 12.41 | 1.93 |
| Cy6 | 13.79 | 15.81 | 1.15 |
| Cy7 | 5.80 | 13.70 | 2.36 |
| Cy8 | 13.37 | 13.45 | 1.01 |
| Cy7-trimer | 8.44 | 12.73 | 1.51 |
| Por-tetracene | ∼0.00a | 6.71 | N/A |
a
A reorganization energy of −0.78 kcal mole−1 is calculated with wb97Xd/6-311+G**. The highly symmetric Por-tetracene systems give rise to degenerate molecular orbitals and virtually identical S0versus S1 structures.