ULTRAFAST ELECTRON-DIFFRACTION - DETERMINATION OF RADICAL STRUCTURE WITH PICOSECOND TIME RESOLUTION

Using ultrafast electron diffraction (UED) with the temporal diffracti on-difference method recently developed in this laboratory, we report accurate determination of the radical (CF2) structure in the dissociat ion of diiododifluoromethane (CF2I2) with picosecond time resolution. Time-zero was clocked accurately within 2 ps and both iodine atoms wer e found to be liberated in less than 4 ps. The structure, absolute fra ction, and electronic state of the radical were determined. The CF2 ra dical was found to be in X(1)A(1) ground state with C-F and F ... F di stances of 1.30(+/-0.02) Angstrom and 2.06(+/-0.06) Angstrom, respecti vely. (C) 1998 Published by Elsevier Science B.V. All rights reserved.