The kinetics of the H_2 (D_2) loss from C_2H_4~+ (C_2D_4~+) ions

摘要

The unimolecular H_2/D_2 loss from C_2H_4~+/C_2D_4~+ ions has been investigated in a threshold photoelectron photoion coincidence spectrometer with electron time of flight discrimination. The experiment shows that the reaction takes place on the microsecond timescale, i.e. is metastable right at the threshold. The experimental breakdown curve for d_4-ethene is shifted by 103 meV to a higher excitation energy compared to h_4-ethene. The entire breakdown curves were simulated based on model k(E) curves. Best agreement between experiment and simulation was observed for threshold values of k(E_0) 7.0 * 10~5 s~(-1) for h_4-ethene and k(E_0) = 2.5 * 10~4 s~(-1) for d_4-ethene.