Vibrational Spectra, DFT Calculations, and the Unusual Structure and Vibrations of 1,3-Disilacylobutane

ORAL

Abstract

The infrared and Raman spectra of 1,3-disilacyclobutane and its 1,1,3,3-d$_{4}$ isotopomer have been reexamined and partially reassigned based on DFT and \textit{ab initio} calculations. These calculations are in excellent agreement with the observed spectra in both frequency and intensity. They also demonstrate that this molecule has CH$_{2}$ wagging and twisting vibrations with frequencies below 1000 cm$^{-1}$, about 200 cm$^{-1}$ lower than expected. These unprecedented low values can be explained by the decreased slope in the potential energy curves for these vibrations as the sideways motions of the CH$_{2}$ groups result in attractive forces between the positively-charged hydrogens on the carbon atoms and the negatively charged hydrogens on the silicon atoms. The theoretical calculations also confirm the previous conclusions that the individual molecules in the vapor have C$_{2v}$ symmetry while in the solid the molecules become planar with D$_{2h}$ symmetry.

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Authors

  • Mohamed Z.M. Rishard

  • Dana Dunn

    University of Texas at Arlington, Peoples Friendship University of the Russia, TSAAPT Officer, University of Texas at El Paso, Department of Chemistry, Stephen F. Austin University, Department of Physics, Stephen F. Austin University, Highland Park High School, Dallas, Texas, Lamar High School, Arlington, Texas, Angelo State University, Abilene Christian University, Southern Nazarene University, Texas Tech University, Sam Houston State University, University of Texas at Austin, Cornell University, University of Houston, University of Texas Center for Relativity, Ion Beam Modification and Analysis Laboratory (IBMAL), University of North Texas, University of North Texas, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, NanoTech Institute, University of Texas at Dallas, Richardson, TX 75083, Department of Physics, The University of Texas at Arlington, Arlington, Texas 76019, Department of Physics, University of Texas at Arlington, Arlington, TX, 76019, UTA High Energy Physics Group, Univ. of Texas, Arlington, USA, KAERI Korea, Changwon National Univ., Korea, Rutgers University, Iowa State University, Rigaku/MSC, Texas Christian University, Dept. of Physics, Changwon National University, Department of Physics, University of North Texas, Department of Chemistry and Biochemistry, Arizona State University, Research Center, Philip Morris USA, Harrington Department Bioengineering Arizona State University, Universidad Autonoma de Colima, Universidad de Buenos Aires, Department of Physics, University of Texas, Arlington, Chair, Department of Physics, University of Texas at Arlington, Dean of Science, University of Texas at Arlington, President, University of Texas at Arlington, Department of Electrical Engineering, Princeton University, Department of Physics, Texas A\&M University, NanoFAB Center and Electrical Engineering Department, University of Texas at Arlington, University of Texas at San Antonio, SEMATECH, University of Texas at Dallas, CINVESTAV Queretaro, Mexico and University of Texas at Dallas, Texas A\&M University, Departamento de F\'isica, FCEN, Universidad de Buenos Aires, Freescale Semiconductor, Inc., Department of Physics, UT Austin, Physics Department, The University of Texas at Arlington, Department of Physics, University of Texas at Arlington, Tolar High School, Granbury High School

  • Jaan Laane

    Department of Chemistry, Texas A\&M University, College Station, TX 77843-3255