The experimental data was taken from
(1) K. Möller, H.-K. Schütze-Pahlmann, J. Hoeft, and T. Törring, 1982, Chem. Phys. 68, 399; and from
(2) W. E. Ernst and T. Törring, 1983, Phys Rev. A 27, 875. Spin-rotation transitions (ΔN = 0) from
(3) W. J. Childs, D. R. Cok, and L. S. Goodmann, 1982, J. Chem. Phys. 76, 3993
were also used in the fit, but they have not been merged because of their weakness.
For transitions with N = 4 – 3 or higher, the hyperfine splitting is smaller than ca. 1 MHz for the strong hfs components. Therefore, predictions without hyperfine structure are also available.
The dipole moment is from
(4) W. E. Ernst, S. Kindt, K. P. R. Nair, and T. Törring, 1984, Phys Rev. A 29, 1158.