Fluoronium, X 1A1
Species tag 021502
Date of EntryNov. 2012
ContributorH. S. P. Müller

Fluoronium, also known as protonated HF, is isoelectronic to H2O. The experimental lines are from
(1) R. Fujimori, K. Kawaguchi, and T. Amano, 2011, Astrophys. J. 729, L2;
and from
(2) T. Amano, F. Matsushima, T. Shiraishi, C. Shinozuka, R. Fujimori, and K. Kawaguchi, 2012, J. Chem. Phys. 137, 134308.
Also used in the fit were infrared transitions from
(3) S. Schä and R. J. Saykally, 1984, J. Chem. Phys. 81, 4189;
these were limited in Ka. Predictions with uncertainties much larger than 1 MHz should be viewed with caution. However, the predictions should be sufficiently accurate for astronomical observations.
The ground state dipole moment is from an ab initio calculation by
(4) P. R. Bunker, P. Jensen, J. S. Wright, and I. P. Hamilton, 1990, J. Mol. Spectrosc. 144, 310.
At low temperatures, it may be necessary to discern between ortho-H2F+ and para-H2F+. The ortho and para states are described by Ka + Kc being odd and even, respectively. The nuclear spin-weights are 3 and 1 for ortho-H2F+ and para-H2F+, respectively. The JKaKc = 101 is the lowest ortho state. It is 21.9624 cm–1 above ground.
Separate para and ortho predictions are available up to J = 5 and Ka = 3 along with separate para and ortho partition function values. Note: the spin-weight of 3 for the separate ortho predictions has been eliminated.

Lines Listed170
Frequency / GHz< 12207
Max. J13
log STR0-5.0
log STR1-3.5
Isotope Corr.-0.0
Egy / (cm–1)0.0
 µa / D 
 µb / D2.59
 µc / D 
 A / MHz1035358.
 B / MHz386552.
 C / MHz271994.
detected in ISM/CSMno

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