Remarks on the OH+ Files

the parameter file;    on the quantum number assignment;    on the extrapolation (a caveat);   

Introduction

The OH+ fit was described in the following publication:

(1) H. S. P. Müller, F. Schlöder, J. Stutzki, and G. Winnewisser,
The Cologne Database for Molecular Spectroscopy, CDMS: a useful tool for astronomers and spectroscopists,
J. Mol. Struct. 742, 215–227 (2005).  View the abstract.

The OH+ data were taken from the following publications:

N = 1 – 0 with FS and HFS:
J. P. Bekooy, P. Verhoeve, W. Leo Meerts, and A. Dymanus,
Submillimeter spectroscopy on OH+: The rotational transition at 1 THz,
J. Chem. Phys. 82, 3868–3869 (1985).

N = 13 – 12 with FS:
D.-J. Liu, W.-C. Ho, and T. Oka,
Rotational spectroscopy of molecular ions using diode lasers,
J. Chem. Phys. 87, 2442–2446 (1987).  View the abstract.

Vibration-rotation transitions up to v = 5 – 4 with FS:
B. D. Rehfuss, M.-F. Jagod, L.-W. Xu, and T. Oka,
Infrared spectroscopy of highly excited vibrational levels of the hydroxyl ion, OH+,
J. Mol. Spectrosc. 151, 59–70 (1992).  View the abstract.


The Parameter File

is setup fairly straightforwardly. States 0-5 represent v = 0 - 5 with fine structure splitting. State 6 codes v = 0 with fine and hyperfine structure splitting.
Because of the different degrees of splitting (with FS and with FS and HFS, respectively) there are 2 option lines !
The parameter ratios for the various states have to be given explicitely for all of the Yi,j. If there is only one isotopic species, this is not necessary for i = 0 !


Remarks on the Quantum Numbers

N, v, J, and F are the quantum numbers. One should be aware of v being a state number representing vibrational quanta only in part. F is not needed for the description of states 0-5, however, F = J has to be used in the line file !


Extrapolation to Higher Quantum Numbers

should always be viewed with caution ! Because of the many infrared transitions used in the fit it is conceivable that the predictions are reliable for low values of N and fairly reliable for higher values of N. In addition, ΔF = ΔJ = ΔN should hold ! "Reliable prediction" means that the transition will be found within three to ten times the predicted uncertainty.