Acta Phys. -Chim. Sin. ›› 2004, Vol. 20 ›› Issue (01): 21-26.doi: 10.3866/PKU.WHXB20040105

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Theoretical Study on Fluorinated Ethylene Cations

Li Wen-Zuo;Huang Ming-Bao   

  1. Department of Chemistry, Graduate School, Chinese Academy of Sciences, Beijing 100039
  • Received:2003-06-24 Revised:2003-08-20 Published:2004-01-15
  • Contact: Huang Ming-Bao

Abstract: Cations of C2H3F+, CF2CH2+, cis-CHF=CHF+, trans-CHF=CHF+, C2HF3+, and C2H4+were studied by using the DFT B3LYP and ab into MP2 methods in conjunction with the 6-31G(d, p), 6-31+G(d, p), 6-311G(d, p), and 6-311+G(d, p) basis sets. Geometry optimization calculations indicate that all the six-fluorinated ethylene cations have planar structures, in contrast with the non-planar D2 structure of the ethylene cation. Differences in geometry between the cations and their parent molecules were examined. Natural population analysis calculations indicate that the positive charge resides mainly at the C atom connecting with the F atom and at the H atoms in these cations. The B3LYP calculations with the 6-311+G(d, p) basis predict vertical and adiabatic ionization potential(VIP and AIP) values of the fluorinated ethylene molecules in good agreement with the experimental values. Diffuse basis functions in the basis sets are important for accurate prediction of the VIPs and AIPs for the fluorinated ethylene molecules.

Key words: Fluorinated ethylene cations, Geometries, Ionization potentials, B3LYP,  MP2