| Cluster | Absorption energy (eV) | Emission energy (eV) |
| NAPA-A | 6.878 | 5.472 |
| NAPA-A (H2O)1 | 7.034 | 5.497 |
| NAPA-A (H2O)2 | 7.015 | 5.490 |
| NAPA-A (H2O)3 | 7.021 | 5.490 |
| NAPA-A (H2O)4 | 7.021 | 5.491 |