| In an intense laser field, atoms and molecules experience tunneling ionization directly to the continuum. We used this method to study several aspects and applications of strong field ionization (SFI) in atoms and molecules. One study used SFI to probe the photofragments produced by photodissociation using DC sliced imaging. The photodissociation mechanism of two polyatomic molecules (sulfur dioxide and nitromethane) were investigated. In a second study, we show the strong field ionization rate depends on the sign of the magnetic number distribution. We detect the signal of sequential double ionization of argon dications by a pump-probe method to investigate the ionization rate sensitivity to circularly polarized light. In a third study, we also found that the modest fragmentation that accompanies strong field ionization may be used to identify isomers and molecules in a complex mixture based on their mass spectral "finger print". The experiments were carried out in a DC sliced imaging apparatus. For the isomer selective detection experiment, the machine was used simply as a time-of-flight mass spectrometer. The mass spectrum of each isomer was used as "basis function" to characterize the complex mixtures quantitatively. |
