Gas phase infrared spectrum and ab initio calculations of phosphorus(III) thiocyanide, SPCN.

An attempt has been made to record the gas phase infrared spectrum of phosphorus(III) thiocyanide, SPCN, for the first time. The molecule was generated by an on-line process using phosphorus(III) thiochloride, SPCl, as a precursor passed over heated silver cyanide at about 350 degrees C. The products were characterized by the infrared spectra of their vapors. The low resolution gas phase Fourier transform infrared spectrum shows three of six characterized fundamental modes of SPCN within the range of the spectrometer used at 2151, 743 and 622 cm(-1) These three bands were assigned to nu(1)(C[triple bond]N stretch), nu(2)(S=P stretch), and nu(3)(C--P stretch), respectively. Ab initio self-consistent-field (SCF) molecular orbital (MO) and Møller-Plesset second-order perturbation theory (MP2) calculations were performed to determine the geometry, total energy and the vibrational frequencies of SPCN.