Theoretical and experimental studies on the tetrafluoroethylene dication

Abstract

C₂F₄²⁺ is accessible by charge stripping from C₂F₄·⁺ with Q_min.= 19.0 eV for C₂F₄·⁺→C₂F₄²⁺ which is in good agreement with the vertical ionization energy of 19.33 eV predicted by ab initio molecular orbital calculations (4-31G//4-31G); according to these calculations the planar (D_2h) form of C₂F₄²⁺ corresponds to the global minimum, being 3.5 kcal mol^–1(14.6 kj mol ^–1) more stable than its perpendicular (D_2d) isomer in distinct contrast to the analogous ethylene dication species for which the perpendicular form represents the global minimum on the C₂H₄²⁺ potential energy surface.