Long-lived excited electronic states of the dichloroethylene cation isomers probed by charge exchange ionization

Charge exchange technique has been used to detect the presence of long-lived excited electronic states of trans-, cis-, and 1,1-C₂H₂Cl ₂ ^+· . The \(\tilde B\) states of the three cations which are formed by removal of an electron from an in-plane chlorine nonbonding orbital of the corresponding neutrals have been found to have long lifetimes (tens of microseconds or longer). Whether the à states formed by removal of an electron from the other in-plane chlorine nonbonding orbitals are long-lived also can not be determined by the present experiments. Cations in the excited electronic states above the \(\tilde B\) states were not detected because of their prompt dissociation following intramolecular relaxation or radiative decay.