Two-proton migration in 1,3-butadiene in intense laser fields

Ultrafast proton migration in 1,3-butadiene in an intense laser field (40 fs, 4.5 x 10(14) W cm(-2)) is investigated by using Coulomb explosion coincidence momentum imaging. The spatial distribution maps of a migrating proton reconstructed for the two three-body Coulomb explosion pathways, C(4)H(6)(3+) -> H(+) + CH(3)(+) + C(3)H(2)(+) and C(4)H(6)(3+) -> H(+) + C(2)H(+) + C(2)H(4)(+), reveal that two protons migrate within a 1,3-butadiene molecule, prior to the three body decomposition.