Fourier transform infrared observation of the ν2 stretching mode of the HCCCO radical in solid Ar J. Chem. Phys. 98, 9251 (1993); 10.1063/1.464405Fourier transform far infrared spectroscopy of the ν' 3 vibration of SiC2 in Ar at 10 K A Fourier transform infrared study of the vibrational spectrum of Si 2 C produced by vaporizing mixtures of silicon and carbon-12 or carbon-13 and quenching the products in Ar at 13 K has confirmed a previously observed vibration at 1188.4 cm -1 as the v~ (b 2 ), antisymmetric Si-C stretching mode, and resulted in the identification of a new vibration at 839.5 cm -1 as the vi'(a l ), symmetric Si-Si stretching fundamental. No bending mode has been observed; however, the identification of an absorption at 1354.8 cm -I as the v;(a l ) + V~(b2) combination band is proposed. The results are confirmed by l3C, 29Si, and 30Si isotopic data and are in excellent agreement with the predictions of ab initio calculations carried out by Rittby in collaboration with this work. Force constant adjustment calculations confirm the ground state geometry as a floppy, bent symmetrical structure.
Fourier transform infrared measurements on the spectra of the products of the vaporization of silicon/carbon mixtures trapped in solid argon in concert with ab initio calculations using second order many body perturbation theory have resulted in the identification for the first time of two vibrational fundamentals, 3 (b 1u )ϭ982.9 and 4 (b 2u )ϭ382.2 cm Ϫ1 , of the rhombic ground state structure of Si 2 C 2 . The observed frequencies, intensities, and isotopic shifts are in good agreement with the ab initio predictions. Tentative assignments are also made for fundamentals of the linear ͑SiCCSi͒ and distorted trapezoidal isomers. The relative energies of the three isomers have been estimated at various ab initio levels.
The products of vaporization of boron/carbon mixtures around 3000 K were trapped in argon matrices at 10 K and their Fourier transform infrared spectra were measured. Analysis of the spectra combined with the predictions of density functional theory (DFT) calculations have resulted in the assignment of a previously observed vibration at 1194.4 cm−1 to the ν2 fundamental of cyclic BC2, which is effectively symmetric. The assignment is supported by 10B, 11B, and 13C isotopic data and is in good agreement with the theoretical predictions.
Articles you may be interested inElectronic structure of diatomic boron nitride Fourier transform infrared measurements on the spectra of the products of the vaporization of silicon/carbon mixtures trapped in argon at ϳ10 K combined with the results from a published ab initio study and from new theoretical calculations carried out in the present work, have resulted in the first observation of a spectrum for the pentagonal Si 3 C 2 cluster. Three vibrational fundamentals have been assigned: the 2 ͑a 1 ͒ symmetric ''breathing'' vibration at 681.1 cm Ϫ1 , the 7 ͑b 2 ͒ Si ␣ -C-C-Si ␣ stretching deformation at 956.7 cm Ϫ1 , and the 8 ͑b 2 ͒ C-Si  -C antisymmetric stretching vibration at 597.8 cm Ϫ1 . The observed frequencies, relative intensities, and 13 C, 29 Si, and 30 Si isotopic shifts are in excellent agreement with the theoretical predictions.
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