| Simple picture of polyacenes and poly-p-phenylenes |
| a |
| Benzene |
| a |
| a |
| A circular ring
of length L = 6a |
| a |
| a |
| 6 unpaired pz
electrons (1 per C) |
| a |
|
|
| Free electron
perspective: |
|
| (works
best for polyacenes) |
|
| Energy levels |
| +2 |
| -2 |
| +1 |
| -1 |
| 0 |