Vibrational spectra of tetra-atomic silicon–carbon clusters. I. Rhomboidal Si3C in Ar at 10 K

Abstract

The vibrational spectrum of Si 3 C has been observed for the first time in a Fourier transform infrared study of the products of the vaporization of carbon/silicon mixtures trapped in Ar at 13 K. Five of the six fundamental modes have been assigned: the symmetric breathing vibration, VI (a l ) = 658.2 cm-I ; the Sip-Sia-Sip symmetric deformation vibration, v 2 (a l ) = 511.8 cm-I ; the Sip-C--Sip symmetric deformation vibration, v 3 (a l ) = 309.5 cm-I ; the Sip-C antisymmetric stretching vibration, v 5 (b 2 ) = 1101.4 cm-\ and the Sia-Sip antisymmetric stretching vibration, v 6 (b 2 ) = 357.6 cm -I. The assignments are supported by 13C, 29Si, and 30Si isotopic data and are in excellent agreement with the predictions of an ab initio study carried out by Rittby in collaboration with this work. The results of force constant adjustment calculations are consistent with the ground state geometry established by the ab initio calculation, a rhomboidal structure of C 2v symmetry, with carbon-silicon transannular bonding between the two equivalent Sip atoms.

Predictive coupled-cluster isomer orderings for some SinCm (m, n ≤ 12) clusters: A pragmatic comparison between DFT and complete basis limit coupled-cluster benchmarks

“…The first observation of visible-range interstellar absorption bands corresponding to Si n C m clusters were reported in 1926 by Merrill 21 rhomboidal Si 3 C, 45 pentagonal Si 3 C 2 , 46 and silicon-rich Si n C (with n = 3-8) 47 and Si n C m (with n + m = 6) clusters. 48 Computational modeling has also been performed by several groups in order to describe small ground-state Si n C m clusters, [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] heterofullerenes, [68][69][70][71] cage structures, 72 silafullerenes, 73 and graphene-silicene bilayers.…”

Ab initio investigation of the stability of Si3C3 clusters and their structural and bonding features

“…The study of silicon-carbon clusters is very important not only because their properties could provide new insight into the physical and chemical behavior of the parent materials, but also on its own right. The threeand four-atom species Si 2 C, SiC 2 , Si 3 C, SiC 3 and Si 2 C 2 have been investigated both experimental [ 14] and theoretically [15][16][17][18], but less is known for the other species.…”

Fourier transform infrared observation of the ν1(σ) mode of linear SiCH in Ar at 10 K

“…It has often been possible to observe 29 Si and 30 Si isotopic shifts in their respective, 4.7% and 3.1% natural abundances in the spectra of silicon-carbon clusters produced by high temperature evaporation, [13][14][15][16] but the relatively weak absorption lines in the present spectra obtained by VUV photolysis make this problematic, even though the predicted 29,30 Si isotopic shifts are large enough to move them outside the envelope of the fundamental absorptions. Nevertheless, because there is no evidence of the vibrational spectra of containing two ͑e.g., Si 2 C 13 and Si 2 C 2 ͒, 14 or more Si atoms ͓e.g., Si 3 C ͑Ref.…”