Photofragment ion imaging from mass-selected MgBrCH complex: Dissociation mechanism following photoinduced charge transfer.

We have observed fragment ion images produced by ultraviolet photodissociation of MgBrCH complex ions using a reflectron time-of-flight mass spectrometer combined with an imaging detector. The BrCH fragment ion was produced after the 266-nm excitation of MgBrCH. In the image of the BrCH ions, a split distribution was observed parallel to the polarization direction of the photolysis laser. In calculated potential energy curves, we found a repulsive potential correlated with a dissociation limit of Mg + BrCH: The calculation results indicate that the dissociation and the charge transfer occurred via non-adiabatic process after the 5A' ← 1A' photoexcitation. The obtained energy and angular distributions of BrCH photofragments were consistent with the fast BrCH formation process on the repulsive potential energy curve.