Infrared, Raman and far infrared spectra, ab initio calculations, and internal rotation of 3-fluoro-3-methyl-1-butyneElectronic supplementary information (ESI) available: symmetry coordinates for vibrations (Table S1), symmetry selection rules for torsional transitions (Table S2), minimum, maximum and saddle point of potential function (Table S3), and predicted infrared and Raman intensities (Table S4). See http://www.rsc.org/suppdata/cp/b4/b404641b/.