title: Coulomb explosion of nitrogen and oxygen molecules through non-Coulombic states.
abstract: We have systematically studied Coulomb explosion of nitrogen and oxygen molecules in intense 8 and 24 fs laser pulses. In the experiment, we explicitly separated all explosion pathways through coincident measurements. The high resolution kinetic energy releases (KERs) and the exotic angular distributions of atomic ions provide direct evidence that Coulomb explosion occurs through non-Coulombic states. In the theory, we calculated dissociation potential energy curves (PECs) of nitrogen and oxygen molecules and their multicharged molecular ions using multiconfiguration second-order perturbation theory. The results indicate that Coulomb potentials are close to the accurate PECs of multicharged molecular ions only when the internuclear distance is larger than 3 Å. In comparison with the experimental observations and the theoretical calculations, we determined the internuclear distance when Coulombic explosion occurs. It is near the equilibrium distance of the neutral molecules in the case of 8 fs laser pulses and expands gradually with the increase of the charge state of the molecular ions in the case of 24 fs laser pulses.
authors: State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871, People's Republic of China.
authors: Chengyin
authors: C
authors: Wu
authors: Yudong
authors: Y
authors: Yang
authors: Zhifeng
authors: Z
authors: Wu
authors: Bozhen
authors: B
authors: Chen
authors: Hua
authors: H
authors: Dong
authors: Xianrong
authors: X
authors: Liu
authors: Yongkai
authors: Y
authors: Deng
authors: Hong
authors: H
authors: Liu
authors: Yunquan
authors: Y
authors: Liu
authors: Qihuang
authors: Q
authors: Gong