VIBRATIONAL AND ROTATIONAL SPECTRA AND AB-INITIO CALCULATIONS OF THIOCYANATOETHENE

Raman spectra of thiocyanatoethene (TCE) as a liquid at various temperatures and of the amorphous and crystalline solids at liquid nitrogen temperature were recorded. IR spectra in the 4000-400 cm(-1) region of the vapour, liquid, amorphous and crystalline solids at low temperature, and of the compound isolated in argon and nitrogen matrices at 5 K with the hot nozzle technique were obtained. Microwave spectra of TCE were recorded in the 10-39 GHz region employing Stark modulation. Areas of special interest were also investigated by use of the RFMWDR double resonance technique. Ab initio calculations with different basis sets were carried out. The compound exists as a mixture of syn and gauche conformers in the vapour and liquid states, while the more stable syn was present in the crystal. An enthalpy difference of 5.7(10) kJ mol(-1) and a barrier of 8.4(3) kJ mol(-1) was found.