Nuclear dynamics on the light-dressed potential energy surface of CS2 by coincidence momentum imaging

The non-sequential three-body Coulomb explosion, CS23+ → S+ + C+ + S+, in an intense laser field (0.2 PW/cm2, 60 fs) is studied by the coincidence momentum imaging of the fragment ions. The observed angular distribution of the momentum vectors of the two S+ ions, p1(S+) and p2(S+), exhibits a peak at an angle as small as θ12∼140°, showing that the nuclear motion is induced along the bending coordinate to a large extent prior to the explosion. On the other hand, the difference between their absolute values, Δp12=|p1(S+)|−|p2(S+)|, has a sharp distribution peaked at Δp12=0, suggesting that the symmetric stretching motion dominates over the antisymmetric stretching motion in the laser field. Based on the energy dependence of the momentum vector correlation, the characteristic nuclear dynamics of CS2 on the light-dressed potential energy surfaces in an intense laser field is discussed.