Vibrational spectra of tetra-atomic silicon–carbon clusters. II. Si2C2 in Ar at 10 K (original) (raw)

Vibrational spectra of penta-atomic silicon–carbon clusters. III. Pentagonal Si3C2

The Journal of Chemical Physics, 1996

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.

An ab initio study of the structure and infrared spectrum of Si2C

The Journal of Chemical Physics, 1991

The ground state geometry and vibrational spectrum of the previously not studied siliconcarbon cluster Si, C has been investigated. Several possible isomeric structures are studied at the Hartree-Fock level. The energetically most favorable isomer is found to be a rhomboidal C,, structure with two equivalent silicon atoms and a transannular Si-C bond. Harmonic frequencies, isotopic shifts, and infrared intensities are calculated using many-body perturbation theory to second order and found to be in excellent agreement with recent experimental results supporting the identification of a new tetra-atomic silicon-carbon cluster.

Vibrational spectra of hexa-atomic silicon-carbon clusters. I. Linear SiC[sub 4]Si

The Journal of Chemical Physics, 1997

Fourier transform infrared measurements on the spectra of the products of the evaporation of silicon/carbon mixtures trapped in Ar at ϳ10 K, combined with the results of ab initio calculations published earlier, and density functional theory ͑DFT͒ calculations carried out in the present work, have resulted in the detection for the first time of the linear SiC 4 Si cluster. Two vibrational fundamentals have been assigned, the CϭC stretching mode 4 ( u )ϭ1807.4 cm Ϫ1 , and the Si-C stretching mode 5 ( u )ϭ719.1 cm Ϫ1 . The observed frequencies, relative intensities, and isotopic shifts are in very good agreement with the results of the DFT calculations and confirm the previously predicted, linear symmetric geometry for the ground state of SiC 4 Si.

An ab initio study of the structure and infrared spectrum of Si2C3

The Journal of Chemical Physics, 1994

An ab initio study of the structure and infrared spectrum of Si3C

The Journal of Chemical Physics, 1992

Ab initio structures and energetics of selected hydrogenated silicon clusters containing six to ten silicon atoms

Chemical Physics Letters, 1999

The structures and energies of eight fully saturated polycyclic polysilanes Si H , H were investigated using ab initio molecular orbital calculations. Structures and vibrational 9 14 10 14 10 16 Ž . Ž . frequencies were computed at the HFr3-21G d level. A complete basis set extrapolation method CBS-4 was used to calculate the energies of the structures. Heats of formation were evaluated based on homodesmotic reactions involving disilane, trisilane, and isotetrasilane. The calculations predict a negative free energy of reaction for cluster formation from Ž . silane with H as a by-product for conditions typically used in chemical vapor deposition of silicon from silane. q 1999 2 Elsevier Science B.V. All rights reserved.

Vibrational spectra of tetra-atomic silicon–carbon clusters. II. Si2C2 in Ar at 10 K (original) (raw)

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