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The Ground and First Excited Torsional States of Acetic Acid



Vadim V. Ilyushin, E A. Alekseev, S K. Dyubko, S V. Podnos, I Kleiner, L Margules, G Wlodarczak, J Demaison, J Cosleou, B Mate, E N. Karyakin, G Y. Golubiatnikow, Gerald T. Fraser, R D. Suenram, Jon T. Hougen


A global fit of microwave and millimeter wave rotational transitions in the ground and first excited torsional states (vt = 0 and 1) of acetic acid (CH3COOH) is reported, which combines older measurements from the literature with new measurements from Lille, NIST, and Kharkov. The fit uses a model developed initially for acetaldehyde and methanol type internal rotor molecules. It requires 34 parameters to achieve a unitless weighted standard deviation of 1.10 for a total of 2411 data, and includes A and E species transitions with J # 30 and Ka # 15. While these results represent a significant improvement over past fitting attempts, it should be cautioned that the present data set is dominated by vt = 0 transitions, and no direct infrared measure of the vt = 1 - 0 torsional interval is available.
Journal of Molecular Spectroscopy
No. 2


acetic acid, global fit, internal rotation, microwave spectrum, torsion-rotation Hamiltonian


Ilyushin, V. , Alekseev, E. , Dyubko, S. , Podnos, S. , Kleiner, I. , Margules, L. , Wlodarczak, G. , Demaison, J. , Cosleou, J. , Mate, B. , Karyakin, E. , Golubiatnikow, G. , Fraser, G. , Suenram, R. and Hougen, J. (2001), The Ground and First Excited Torsional States of Acetic Acid, Journal of Molecular Spectroscopy (Accessed April 20, 2024)
Created January 31, 2001, Updated October 12, 2021