Table 3. Excited and Optical Properties of the Clustersa.
| cluster | Egap [eV] | Eopt [eV] | Eb [eV] |
|---|---|---|---|
| MgF2 | 12.49 | 6.78 (0.14; H-3 → L, H-2 → L) | 5.71 |
| (MgF2)2 | 11.48 | 6.56 (0.03; H-1 → L, H → L+1) | 4.92 |
| (MgF2)3 | 11.15 | 6.66 (0.03; H-1 → L, H-1 → L+1, H → L) | 4.49 |
| CaF2 | 10.90 | 5.64 (5.9 × 10–5; H → L) | 5.19 |
| (CaF2)2 | 10.04 | 5.42 (1.9 × 10–4; H-1 → L, H → L) | 4.62 |
| (CaF2)3 | 9.84 | 5.39 (1.1 × 10–4; H → L, H → L+4) | 4.45 |
| SrF2 | 10.16 | 5.26 (7.0 × 10–4; H → L) | 4.9 |
| (SrF2)2 | 9.60 | 5.11 (1.6 × 10–3; H-2 → L) | 4.49 |
| (SrF2)3 | 9.33 | 5.10 (4.0 × 10–4; H-1 → L) | 4.23 |
| BaF2 | 9.98 | 5.40 (8.0 × 10–4; H → L) | 4.58 |
| (BaF2)2 | 9.24 | 5.25 (1.6 × 10–3; H → L) | 3.99 |
| (BaF2)3 | 9.15 | 5.40 (1.3 × 10–3; H → L) | 3.75 |
a
The quasiparticle gap (Egap), the optical onset (Eopt in bold), and the binding energy of the exciton (Eb) are given. In the third column, for Eopt, the oscillator strength of the transition followed by the states involved in the transition in the form initial state → final state with H for HOMO and L for LUMO states is given in parentheses.