GEOMETRY AND NATURE OF THE BINDING OF THE PRE-REACTIVE COMPLEX C2H4-CENTER-DOT-CENTER-DOT-CENTER-DOT-CLF FROM ITS ROTATIONAL SPECTRUM

The encounter complex C2H4...ClF was isolated by using a fast-mixing n ozzle before chemical reaction could occur between the components and was characterised by Fourier-transform microwave spectroscopy. Rotatio nal constants, centrifugal distortion constants, Cl nuclear quadrupole constants and Cl spin-rotation constants were determined for the isot opomers C2H4...(ClF)-Cl-35 and C2H4...(ClF)-Cl-37. The complex has C-2 v symmetry with the ClF subunit perpendicular to the plane of C2H4 and oriented so that Cl is closer to C2H4. Both the centrifugal distortio n constant Delta(J) and the Cl nuclear quadrupole coupling constants i ndicate that the complex is relatively weakly bound and it is conclude d that the interaction between the subunits is largely electrostatic i n origin.