The anti-anti conformer, also known as the trans-trans conformer, is the lowest state conformer of diethyl ether. The experimental lines are from
(1) I. Medvedev, M. Winnewisser, F. C. DeLucia, E. Herbst, E. Yi. L. P. Leong, R. P. A. Bettens, E. Bialkowska-Jaworska, O. Desyatnyk, L. Pszczólkowski, and Z. Kisiel, 2003, Astrophys. J. Suppl. Ser. 148, 593.
The data set also includes few lines from
(2) M. Hayashi and K. Kuwada, 1974, Bull. Chem. Soc. Japan., 47, 3006.
With respect to the Nov. 2003 entry, the FASSST data from (1) have been replaced by corresponding values from
(3) Z. Kisiel, L. Pszczólkowski, I. Medvedev, M. Winnewisser, F. C. DeLucia, E. Herbst, 2005, J. Mol. Spectrosc. 233, 231;
and submillimeter data from
(4) A. Walters, H. S. P. Müller, F. Lewen, and S. Schlemmer, 2009, J. Mol. Spectrosc. 257, 24.
Transitions with uncertainties larger than 50 and 100 kHz have not been merged for measurements below and above 100 GHz, respectively.
The predictions are considered to be reliable throughout.
The dipole moment is from (1).
As in (1), spin-statistics have not been taken into account because the nuclear spin-weight ratio is very close to 1. Tunneling is negligible in this conformer.
Note: The partition function was calculated neglecting vibrationally excited states and higher-lying conformers. See also e074515.cat for the anti-gauche conformer.