Argonium, 1Σ+, 36Ar isotopic species
Species tag 037502
Date of EntrySep. 2007
ContributorH. S. P. Müller

Pure rotational as well as rovibrational data of several isotopic species of ArH+ have been fit simultaneously.
The J = 1 – 0 transition frequency was reported in
(1) K. B. Laughlin, G. A. Blake, R. C. Cohen, D. C. Hovde, and R. J. Saykally, 1987, Phys. Rev. Lett., 58, 996.
Additional lines up to J = 7 – 6 were taken from
(2) 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
(3) 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
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
(5) D. J. Liu, W. C. Ho, and T. Oka, 1987, J. Chem. Phys. 87, 2442.
Rovibrational transitions of ArH+ were recorded by
(6) 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
(7) J. W. C. Johns, 1984, J. Mol. Spectrosc. 106, 124.
Infrared data for 36ArH+ and 38ArH+ was provided by
(8) 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 36ArH+; reliable predictions can be derived from the available species.
The dominant intersteller argon isotope is 36Ar. 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.
Note: July 2012: the rest frequencies provided for 36ArH+ actually refered the the first excited vibrational state. This has now been corrected. Version number and date have been retained. Thanks to Al Wooten for pointinmg this out.
The partition function takes into account all vibrational states used in the fit. Non-zero contributions of individual vibrational states to the partition function are given in parentheses.
The dipole moment was assumed to agree with that of the main species, see e041504.cat.

Lines Listed27
Frequency / GHz< 15246
Max. J27
log STR0-15.0
log STR1-15.0
Isotope Corr.-2.473
Egy / (cm–1)0.0
 µa / D2.177
 µb / D 
 µc / D 
 Q(1000.)70.1261 (68.3714, 1.7024, 0.0504, 0.0018, 0.0001)
 Q(500.0)34.2326 (34.2122, 0.0204)
 Q(300.0)20.6293 (20.6293, 0.0001)
 Q(225.0)15.5478 (15.5478)
 Q(150.0)10.4739 (10.4739)
 Q(75.00)5.4108 (5.4108)
 Q(37.50)2.8930 (2.8930)
 Q(18.75)1.6617 (1.6617)
 Q(9.375)1.1275 (1.1275)
detected in ISM/CSMyes

Database maintained by Holger S. P. Müller and Sven Thorwirth, programming by D. Roth and F. Schloeder