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This entry only deals with transitions of ammonia in
its ground vibrational state for which 14N
and potentially even 1H hyperfine structure
splitting may be resolved in astronomical sources.
The entry is based on preparatory work for
(1) S. Yu, J. C. Pearson, B. J. Drouin, K. Sung, O. Pirali,
M. Vervloet, M.-A. Martin-Drumel, C. P. Endres, T. Shiraishi,
K. Kobayashi, and F. Matsushima,
2010, J. Chem. Phys. 133, Art. No. 174317;
which led to versions 5 of ammonia in v = 0 and
v2 = 1 of the JPL catalog from Sep. 2010 with
tags 017002 and 017004, respectively.
Additional information on this data set was
given by
(2) B. J. Drouin, S. Yu, and J. C. Pearson,
contribution TC 10 presented at the 65th International
Symposium on Molecular Spectroscopy, Columbus, OH, USA,
June 21–25, 2010.
The experimental ground state inversion frequencies with
HFS splitting were taken from
(3) S. G. Kukolich,
1967, Phys. Rev. 156, 83;
for JK = 11,
22, 33, and 32.
(4) S. G. Kukolich and S. C. Wofsy,
1970, J. Chem. Phys. 52, 5477;
for 21, 31, 42,
44, and 55.
(5) S. G. Kukolich,
1965, Phys. Rev. 138, A 1322;
for 32.
(6) D. J. Ruben and S. G. Kukolich,
1974, J. Chem. Phys. 61, 3780;
for 53.
The ground state rotation-inversion transition was
reported by
(7) G. Cazzoli, L. Dore, and C. Puzzarini,
2009, Astron. Astrophys. 507, 1707.
The number of parameter was substantially reduced
for the present entry. Most notably, two sets of
decic and dodecic parameters were reduced to one each
because for the pure inversion transitions only
differences in the spectroscopic parameters can be determined.
The number of ground state quadrupole distortion parameters
and their magnitudes are too large. However, no quick
solution was found, and the parameters were retained.
Instead, it is recommended to view the calculations
with caution for J or K above 3.
The quantum numbers for the regular entry are
J, K, v, and F, as usual;
v = 0 stands for 0+ (or vt
= 0; v = 1 stands for 0–
(or vt = 1. F includes here
the 14N spin.
1H hyperfine splitting may matter
in astronomical observations. Therefore, a
separate hyperfine calculation is provided for
J ≤ 6 below 26 GHz.
The quantum numbers here are
J, K, v, n, and F;
where n is an aggregate spin number that can be
disentangled using the part of the out file that is provided.
Please note that F, the total spin, now including those
of the H nuclei, was rounded up to the next integer.
NOTE: The partition function
does take into account the spin multiplicity
of the 1H nuclei !
A separate hyperfine calculation with
seven quantum numbers is also available.
The quantum numbers in this case are
J, K, v, F1,
F2, Itot, and F;
where F1 includes the 14N spin,
F2 is redundant and maybe not meaningful,
but needed in the program, Itot is the
total spin of the hydrogen nuclei rounded up to the next
digit, and F as above.
The dipole moment and its first order distortion
corrections were taken from
(7) K. Tanaka, H. Ito, and T. Tanaka,
1987, J. Chem. Phys. 87, 1557.
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