| C6 | C8 | C10 | Ref. |
|---|---|---|---|
| 1.384[4] | 3.539[6] | 1.064[9] | M. Marinescu and A. Dalgarno, Phys. Rev. A 52, 311 (1995) |
| 1.365[4] | 3.392[6] | n/a | B. Bussery and M. Aubert-Frecon, J. Mol. Spectrosc. 115, 169 (1986) |
| 1.365[4] | 3.431[6] | 1.014[9] | F. Vigne-Maeder, Chem. Phys. 85, 139 (1984) |