| C6 | C8 | Ref. |
|---|---|---|
| 1.3447[3] | -1.0569[4] | M. Marinescu, Phys. Rev. A 56, 4764 (1997) |
| 1.36[3] | n/a | M. Rerat, B. Bussery, and M. Frecon, J. Mol. Spectrosc. 182, 260 (1997) |
| 1.26[3] | n/a | M. Rerat, B. Bussery, and M. Frecon, J. Mol. Spectrosc. 182, 260 (1997) |
| 1.157[3] | n/a | B. Bussery and M. Frecon, J. Mol. Spectrosc. 115, 169 (1989) |
| 1.5(0.2)[3] | n/a | D. D. Konowalow and J. Fish, Chem. Phys. 77, 435 (1983) |