Theoretical study on isomeric stabilities of C2H2Si and its ionization potentials and electron affinities.
| Autor: | Ikuta S; Tokyo Metropolitan University, Computer Center, 1-1 Minami-Ohsawa, Hachioji-shi, Tokyo 192-0397, Japan. ikuta@cop.metro-u.ac.jp, Saitoh T, Wakamatsu S |
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| Jazyk: | angličtina |
| Zdroj: | The Journal of chemical physics [J Chem Phys] 2004 Aug 22; Vol. 121 (8), pp. 3478-85. |
| DOI: | 10.1063/1.1777217 |
| Abstrakt: | The geometric structures and isomeric stabilities of various stationary points in C(2)H(2)Si neutral and its cation and anion are investigated at the coupled-cluster singles, doubles (triples) [CCSD(T)] level of theory. For the geometrical survey, the basis sets used are of the Dunning's correlation consistent basis sets of triple-zeta quality (cc-pVTZ) for the neutral and cation. For the anions, the cc-pVTZ basis sets with diffuse functions (aug-cc-pVTZ) are used. The final energies are calculated by the use of the CCSD(T) level of theory with the aug-cc-pVTZ basis set at their optimized geometries. To lower lying neutrals and cations, the Dunning's correlation consistent basis sets of quadruple-zeta quality (cc-pVQZ) are also applied. Both the global minima of the C(2)H(2)Si neutral and cation, N-1 (C(2v):(1)A(1)) and C-1 (C(2v):(2)B(2)), respectively, are silacyclopropenylidene conformers, having a CCSi ring with a C[Double Bond]C double bond. No competitive stable isomers exist in the present C(2)H(2)Si neutral. In the cation, however, the second lowest lying isomer C-2 lies 10.8 kJ/mol above the most stable C-1. The vertical and adiabatic ionization potentials from the lowest lying neutral N-1 are 9.83 and 8.97 eV, respectively, at the CCSD(T)/cc-pVQZ level of theory. The electron addition to the N-1 does not result in the anion with positive (real) electron affinities. On the other hand, the electron addition to the N-2 isomer produces the global minimum anion A-1 (C(2v):(2)B(1)) with the positive electron affinities of 1.13 eV. The second lowest lying anion isomer A-2 with silylenylacetylene conformer, produced from an electron addition to the N-3 neutral, very well competes with the A-1 after the zero-point vibrational energy corrections. The energy difference between the two lowest lying isomers of the neutral and its anion, N-1 and A-1, is only 0.39 eV. ((c) 2004 American Institute of Physics) |
| Databáze: | MEDLINE |
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