Atomic ionization by intense mid-infrared (mid-IR) pulses produces low electron energy features that the strong-field approximation, which is expected to be valid in the tunneling ionization regime characterized by small Keldysh parameters (γ 1), cannot describe. These features include the low-energy structure (LES), the very-low-energy structure (VLES), and the more recently found zero-energy structure (ZES). They result from the interplay between the laser electric field and the atomic Coulomb field which controls the low-energy spectrum also for small γ. In the present joint experimental and theoretical study we investigate the vectorial momentum spectrum at very low energies. Using a reaction microscope optimized for the detection of very low energy electrons,we have performed a thorough study of the three-dimensional momentum spectrum well below 1 eV. Our measurements are complemented by quantum and classical simulations, which allow for an interpretation of the LES, VLES and of the newly identified ZES in terms of two-dimensionalCoulomb focusing and recapture into Rydberg states, respectively.

Abstract AbstractUncomplicated reflux disease comprises the non-erosive reflux disease (NERD) and erosive reflux disease (ERD). The objectives of treatment are the adequate control of symptoms with restoration of quality of life, healing of lesions and prevention of relapse. Treatment of NERD consists in the administration of proton pump inhibitors (PPI) for 2-4 wk, although patients with NERD show an overall poorer response to PPI treatment than patients with ERD owing to the fact that patients with NERD do not form a pathophysiologically homogenous group. For long-term management on-demand treatment with a PPI is probably the best option. In patients with ERD, therapy with a standard dose PPI for 4-8 wk is always recommended. Long-term treatment of ERD is applied either intermittently or as continuous maintenance treatment with an attempt to reduce the daily dosage of the PPI (step-down principle). In selected patients requiring long-term PPI treatment, antireflux surgery is an alternative option. In patients with troublesome reflux symptoms and without alarming features empirical PPI therapy is another option for initial management. Therapy should be withdrawn after initial success. In the case of relapse, the long-term care depends on a careful risk assessment and the response to PPI therapy.

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