FOURIER TRANSFORM INFRARED STUDIES OF THE VIBRATIONAL SPECTRA OF HYDROGEN BEARING SILICON-CARBON CLUSTERS IN Ar AT 10 KaK^{a}

$^{a}$Work supported by the Welch FoundationAuthor Institution: Department of Physics, Texas Christ tan UniversityFourier transform infrared studies of small hydrogen bearing silicon-carbon clusters [rapped in solid Ar have resulted in the identification of new species. Among those so far investigated is the linear SiCCH radical produced from the products of the vacuum ultraviolet photolysis of a mixture of $SiH_{4}$., silane. and $C_{2}H_{2}$, acetylene. Two fundamentals of SiCCH have been observed, the $\nu_{2}(\sigma)$, carbon-carbon stretching mode at $1989.8 cm^{-1}$ and the $\nu_{3}(\sigma)$, silicon-carbon stretching mode at $636.0 cm^{-1}$. Also investigated is SiCH produced by the photolysis of $SiH_{4}$ and $CH_{4}$ methane. The identification of vibrational modes and determination of structures for these species is based on comparison of measured frequencies, relative intensities and the results of extensive measurements of D and $^{13}C$ isotopic shifts with the results of {ab initio} calculations performed in conjunction with this work

FOURIER TRANSFORM INFRARED DETECTION AND ISOTOPIC STUDY OF THE SiC2HSiC_{2}H MOLECULE IN AN Ar MATRIX AT 10K

1. C.M.L. Rittby, results of unpublished CCSD calculation.Author Institution: Texas Christian University, Fort Worth, TX 76129.The vibrational fundamentals of the $SiC_{2}H$ molecule have been observed for the first time, by trapping the products of the vacuum ultraviolet photolysis of silane and acetylene in an Ar matrix at 10 K. Isotopic shifts for deuterium and carbon-13 have been obtained to support the identification of the $\nu_{2} (\sigma)$ carbon-carbon stretching vibration at $1998.8 cm^{-1}$. The observed frequencies of vibrational fundamentals and isotopic shifts are in good agreement with ab initio $calculations.^{1}$ A full analysis of vibrational fundamentals will be presented

FIRST DETECTION OF THE ν7(σu)\nu_{7}(\sigma_{u}) STRETCHING FUNDAMENTAL OF LINEAR C9C_{9} AND STUDY OF THE ν5(σu)\nu_{5}(\sigma_{u}) MODE OF LINEAR C7C_{7} IN Ar AT 10 K

1. J.R. Heath and R.J. Saykally, J. Chem, Phys, 93, 8392 (1990).Author Institution: Texas Christian University, Fort Worth, TX 76133.Recent ab initio calculations for the linear $C_{9}$ carbon cluster have shown a notable lack of convergence in the values of the frequencies and intensities predicted for the antisymmetric stretching modes $\nu_{5}, \nu_{6}$, and $\nu_{7}$. This situation has motivated a search for a second antisymmetric fundamental in addition to the $\nu_{5}(\sigma_{u})$ already observed at $2014.28 cm^{-1}$ in the gas $phase.^{1}$ This paper reports Fourier transform infrared observations of $C_{9}$ in solid Ar resulting in the identification for the first time of the $\nu_{7}(\sigma_{u})$ mode at $1601.0 cm^{-1}$. Comparison of $^{13}C$ isotopic shifts measured for over 200 isotopomers with the predictions of DFT (density functional theory) and CCSD (coupled cluster) calculations, conclusively confirms the assignment of the new mode. The results of isotopic measurements for the $\nu_{5}(\sigma_{u})$ antisymmetric stretching mode of linear $C_{7}$ at $1894.3 cm^{-1}$ and comparison with ab initio calculations are also reported

FTIR OBSERVATION AND DFT STUDY OF THE AlC3_3 and AlC3_3Al LINEAR CHAINS TRAPPED IN SOLID Ar

Author Institution: Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129The vibrational spectra of linear AlC$_3$ and AlC$_3$Alwere observed after trapping the products of the dual laser evaporation of aluminum and carbon rods in solid Ar at $\sim$10 K. Fourier transform infrared (FTIR) measurements of $^{13}$C isotopic shifts are in good agreement with the predictions of density functional theory (DFT) B3LYP/6-311G+(3\textit{df}) calculations and have enabled the first identification of the $\nu_3$($\sigma$\textit{$_u$})$=$1624.0 and $\nu_4$($\sigma$\textit{$_u$})$=$528.3 cm$^{-1}$ fundamentals of linear AlC$_3$Al and the tentative assignment of the $\nu_2$($\sigma$)$=$1210.9 cm$^{-1}$ fundamental of linear AlC$_3$