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Following our previous work, we carry out a more detailed study of dissociation dynamics of diatomic ions field-evaporated from a metallic tip of field-ion microscopy, We have found that the partial fractal behavior of the dissociation probability near threshold field strength and the multiple peaks in the time-of-flight spectrum can be attributed to different combinations of vibrational and rotational cycles before ions dissociate, But more clear revelation of the origin of the fractal behavior comes from investigating the uniform-field limit, where we show that two types of chaos exist, one is associated with the rotational saddle orbit and the other associated with the moving potential barrier of a DC field-distorted anharmonic oscillator, The homoclinic tangles associated with these saddles give rise to the sensitive dependence of dynamics on initial conditions.

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Direct inversion of measured multiple-energy Kikuchi electron patterns from a Si(001) (2 x 1) surface with glancing and normal-incidence geometry shows clear images of the surface dimer and the bulk atoms. The three-dimensional artifact-free real-space images of the atoms contributed from different local emitters are resolved clearly. The observations demonstrate that Kikuchi electron holography has the surface sensitivity and can reveal the atomic structures of complicated multiemitter systems. By changing the collecting angle of Kikuchi electrons, one can selectively image the atoms behind the emitter in the backward direction; thus the surface and the bulk information can be obtained with different collecting angles. Therefore, the potential of Kikuchi electron holography to solve the local atomic structure of the unknown surfaces is high.

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