Hydrated forms of fluoroacetic acid: a rotational study.

The rotational spectra of two conformers of the 1 : 1 adduct of fluoroacetic acid with water have been assigned by pulsed jet Fourier transform microwave spectroscopy. Their shapes differ according to the trans and cis forms of the fluoroacetic acid moiety. This is in contrast to the rotational spectrum of the monomer, for which the cis form has not been observed. Details of the hydrogen bond, structure, dynamics and energetic features of the two species are given.