Workshop Molecular Photoreactivity on Metal-Oxide Surfaces from First-Principles
Madrid 4th – 5th December 2009
Study about some isomers of the SiC3 and Prediction of Reactive Sites for
SiC3H Using Electron Localization Function (ELF)
Natalia Inostroza1,2, M. L. Senent1, P. Fuentealba3, J. R. Letelier4
1 Instituto de Estructura de la Materia, C.S.I.C, Departamento de Astrofísica Molecular e Infrarroja, , Serrano 121 Madrid 28006,España.2 Universidad Andrés Bello, Facultad de Ecología y Recursos Naturales, Departamento de Química, Santiago, Chile,.3 Universidad de Chile, Departamento de Física Facultad de Ciencias, Las Palmeras 3425, Nuñoa, Santiago, Chile, 4Universidad de Chile, Departamento de Ciencia de los Materiales, Facultad de Ciencias Físicas y Matemáticas, Beauchef 850, Santiago, Chile.
The rhomboidal SiC3 isomer has been detected in the expanding envelope of the evolved carbon star IRC+10216 after being identified in laboratory1. Previous theoretical studies established various cyclic and linear2 isomers for C3Si. The study of these series of molecules is important to understand the interstellar silicon–carbon clusters SiCnX (X=N, P, H) and for exploring the new silicon–carbon species in laboratory or interstellar space as well for the study of the mechanism of silicon–carbon material formation.
In the present work using the Electron Localization Function, ELF, we studied the nature of the chemical bonds present in these structural isomers and the possible reactivity of them toward the formation of SiC3H.
The calculation methodologies used to obtain the wave functions have been B3LYP/6-311G (d,p). To obtain representative functions of our systems has been necessary to consider the symmetry of each species. For the analysis and understanding of the electron localization function (ELF)3 we used the codes TOPMOD.
A separation of the ELF functions into its α-spin and β-spin contributions has been performed. The results show that the ELF separation yields complementary information about the localization of the unpaired electron. From the ELFα and ELFβ isosurfaces we can see that in the singlet state the more important contributions in the bond are the same in all isomers, however, they are different in the triplet state.
1. A.J. Apponi, M.C. McCarthy, C. A. Gottlieb, and P. Thaddeus, J.Chem.Phys., 111, 3911 (1999)
2. N. Inostroza, M.L. Senent, M.Hochlaf, J.R. Letelier, Astronomy&Astrophysics ,486, 1047 (2008).
3.P. Fuentealba, E. Chamorro and J, C, Santos, in Theoretical Aspects of Chemical Reactivity, Ed. by A.
Toro, Elsevier 2007.