Mass-resolved momentum imaging of three dichloroethylene isomers by femtosecond laser-induced coulomb explosion

Wada, Yoriko*; Akagi, Hiroshi*; Kumada, Takayuki   ; Itakura, Ryuji*; Wakabayashi, Tomonari*

Coulomb explosion experiments using 60 fs laser pulses were conducted for structural characterization of three dichloroethylene isomers. Under laser intensity at 1.8 10 W/cm, mass-resolved momentum imaging (MRMI) for selected fragment ions of Cl and C revealed different patterns for the three isomers. The C ion fragmented from multiply charged trans-1,2-DCE was forced to leave perpendicularly to the direction of the laser polarization, due to recoil forces from adjacent cations. In contrast, the fast ions of C from cis-1,2-DCE exhibited an isotropic distribution, whereas the fast ions of C from 1,1-DCE recoiled along the laser polarization together with the slow C ions, and thereby distinction of the three isomers was demonstrated. Coulomb explosion occurs predominantly at specific orientation, which is useful for potential applications of MRMI analysis to molecular structure assays.