| C6 | C8 | Ref. |
|---|---|---|
| -7.4299[2] | -2.6182[6] | M. Marinescu, Phys. Rev. A submitted |
| -8.80[2] | -7.820[5] | B. Bussery, Y. Achkar, and M. Aubert-Frecon, Chem. Phys. 116, 319 (1987) |
| -9.00[2] | -3.9547[6] | C. Vadla, C. -J. Lorenzen, and K. Niemax, Phys. Rev. Lett. 51, 988 (1983) |