| F (Hz) | E1 (eV) | E2 (eV) | Temp. ˚C | n1 | n2 |
| 0 | 0.034 | 0.132 | 30 | 0.0012 | 0.437 |
| 103 | 0.022 | 0.075 | 50 | 0.001 | 0.472 |
| 104 | 0.022 | 0.076 | 60 | 0.001 | 0.474 |
| 105 | 0.021 | 0.074 | 80 | 0.0011 | 0.454 |
| 106 | 0.021 | 0.073 | 90 | 0.0012 | 0.447 |
| 107 | 0.029 | 0.065 | 100 | 0.0009 | 0.444 |