Mar. 2017: The value of g_I = 2 was considered for the partition function values, but initially not in the calculation of the intensities. These were consequently too small by a factor of 2. This error has been corrected.
The entry is based on a fit published in
(1) M. Carvajal, I. Kleiner, and J. Demaison, 2010, Astrophys. J. Suppl. Ser. 190, 315.
The experimental frequencies have been taken from
(2) M. Carvajal, L. Margulès, B. Tercero, K. Demyk, I. Kleiner, J. C. Guillemin, V. Lattanzi, A. Walters, J. Demaison, G. Wlodarczak, T. R. Huet, H. Møllendal, V. V. Ilyushin, and J. Cernicharo, 2009, Astron. Astrophys. 500, 1109;
(3) A. Maeda, F. C. De Lucia, and E. Herbst, 2008, J. Mol. Spectrosc. 251, 293;
(4) A. Maeda, I. R. Medvedev, F. C. De Lucia, E. Herbst, and P. Groner, 2008, Astrophys. J. Suppl. Ser. 175, 138;
(5) F. Willaert, H. Møllendal, E. Alekseev, M. Carvajal, I. Kleiner, and J. Demaison, 2006, J. Mol. Struct. 795, 4.
The theoretical formalism used for fitting and predicting the line frequencies is the so-called RAM (Rho-Axis Method). Details on the RAM and on the BELGI code employed to reduce the data is available in
(6) I. Kleiner, 2010, J. Mol. Spectrosc. 260, 1;
and references therein.
Predictions with uncertainties larger than 0.5 MHz should be viewed with some caution.
With respect to the first entry in the CDMS@VAMDC from Aug. 20, 2013, partition function values were used that should be complete up to 300 K. Torsional contributions were determined directly for v_t = 0 and 1, as before. In addition, those for v_t = 2 were extrapolated. Higher torsional contributions up to v_t = 6 were estimated as were contributions from other vibrations in the harmonic approximation. Details are in
(7) C. Favre, M. Carvajal, D. Field, J. K. Jørgensen, S. E. Bisschop, N. Brouillet, D. Despois, A. Baudry, I. Kleiner, E. A. Bergin, N. R. Crockett, J. L. Neill, L. Margulès, T. R. Huet, and Jean Demaison; 2014, Astrophys. J. Suppl. Ser. 215, Art. No. 25.
Additional information on the partition function is also available.
The RAM dipole moment values given below were derived in (1) assuming that the dipole moment agrees with that of the main isotopolog, which was determined by
(8) L. Margulès, T. R. Huet, J. Demaison, M. Carvajal, I. Kleiner, H. Møllendal, B. Tercero, N. Marcelino, and J. Cernicharo, 2010, Astrophys. J. 714, 1120.
Vibrational identifiers 0 and 3 refer to transitions with torsional states having A symmetry in v_t = 0 and 1; 1 and 4 to torsional states having E symmetry with Ka ≥ 0; and 2 and 5 to torsional states having E symmetry with Ka < 0.