Pure rotational as well as rovibrational data of several isotopic species of ArH⁺ have been fit simultaneously.
The rotational spectrum up to J = 7 – 6 was reported by
(1) J. M. Brown, D. A. Jennings, M. Vanek, L. R. Zink, and K. Evenson, 1988, J. Mol. Spectrosc. 128, 587.
The J = 1 – 0 transition frequencies of three ArD⁺ isotopic species involving ⁴⁰Ar, ³⁶Ar, and ³⁸Ar, were published by
(2) W. C. Bowman, G. M. Plummer, E. Herbst, and F. C. De Lucia, 1983, J. Chem. Phys. 79, 2093;
the reported uncertainties for the ⁴⁰Ar and ³⁶Ar species have been increased somewhat.
High-J pure rotational transition frequencies of ArD⁺ were taken from
(3) H. Odashima, A. Kozato, F. Matsushima, S. Tsunekawa, and K. Takagi, 1999, J. Mol. Spectrosc. 195, 356.
High-J pure rotational transitions of ArH⁺ up to high vibrational states were detected in the lower infrared region by
(4) D. J. Liu, W. C. Ho, and T. Oka, 1987, J. Chem. Phys. 87, 2442.
Rovibrational transitions of ArH⁺ were recorded by
(5) J. W. Brault and S. P. Davis, 1982, Physica Scripta 25, 268.
Additional high-v transitions as well as transitions of ArD⁺ were reported by
(6) J. W. C. Johns, 1984, J. Mol. Spectrosc. 106, 124.
Infrared data for ³⁶ArH⁺ and ³⁸ArH⁺ was provided by
(7) R. R. Filueira and C. E. Blom, 1988, J. Mol. Spectrosc. 127, 279.
There is great consistency among essentially all experimental data. Therefore, it may well be that ion drift effects on the reported frequencies are small. Nevertheless, all predictions should be viewed with some caution, especially if the calculated uncertainties exceed 2 MHz by far.
There are no experimental transitions frequencies for ³⁸ArH⁺; reliable predictions can be derived from the available species.
The second most important intersteller argon isotope is ³⁸Ar. The by far dominant isotope on Earth is ⁴⁰Ar, but it originates almost entirely from the radioactive decay of ⁴⁰K. Its relative abundance in the ISM is almost negligible.
The partition function takes into account all vibrational states used in the fit.
The dipole moment was assumed to agree with that of the main species, see e041504.cat.