“…As compared to the tunneling regime of ionization, where the electron escapes to the continuum through the potential barrier suppressed by laser field, above-threshold ionization (ATI) in the multiphoton regime [13] produces an electron of discretized energy by vertically absorbing many photons, interestingly, the channel-resolved single-electron ATI photoelectron spec troscopy [14] allows one to probe the participation of different electronic continua in strong-field single ionization of molecules. Beyond single ionization, exchanging and sharing of the absorbed multiphoton energies by the freed electrons are expected in nonsequential above-threshold double ionization (ATDI) [15][16][17][18][19], Recently, this was observed experimentally in argon atoms [20], To date, however, the experimental demonstration of ATDI is still lacking for strong-field multiphoton ionization of molecules.ATDI of molecules in the multiphoton regime is capable of resolving the rich and complicated multielectron dynam ics of molecules into distinct channels. Among the mani fold photon-induced molecular dynamics, isomerization is one of the most fundamental and interesting processes [21].…”