Role of the molecular electronic configuration in the Coulomb fragmentation of N2, C2H2and C2H4in an intense laser field

The influence of the electronic structure on the molecular response to an intense picosecond laser at lambda =616 nm and I=2*10 15 W cm -2 is investigated for N 2 , C 2 H 2 and C 2 H 4 . The fragmentation pattern into charge-symmetric N Z +N Z'+ and C Z+ +C Z'+ Coulomb fragmentation channels is found to be similar for N 2 and C 2 H 2 which have close ground state electronic configurations. The laser molecule coupling for the production of C Z+ +C Z'+ dissociation pathways is more efficient for C 2 H 2 than for C 2 H 4 due to the respectively different pi 4 and pi 2 electron configuration of the C-C bond. The overall experimental data suggest that the laser energy is absorbed by molecular orbital type electrons, even in the case of a nuclear structure deformation, while the molecule decays into Coulomb fragmentation channels with kinetic energy releases independent of the laser excitation conditions as observed in previous experiments.