Electron Capture from Molecular Hydrogen by Metastable Sn2+* Ions

Over a wide and partly overlapping energy range, the single-electron capture crosssections for collisions of metastable Sn2+(5s5p3Po) (Sn2+∗) ions with H2 molecules were measured(0.1–10 keV) and calculated (0.3–1000 keV). The semi-classical calculations use a close-couplingmethod on a basis of electronic wavefunctions of the (SnH2)2+ system. The experimental crosssections were extracted from double collisions in a crossed-beam experiment of Sn3+ with H2. Themeasured capture cross-sections for Sn2+∗show good agreement with the calculations between2 and 10 keV, but increase toward lower energies, whereas the calculations decrease. AdditionalLandau–Zener calculations were performed and show that the inclusion of spin-orbit splitting cannotexplain the large cross-sections at the lowest energies which we now assume to be likely due tovibrational effects in the molecular hydrogen target

Electron Capture from Molecular Hydrogen by Metastable Sn²⁺* Ions

Over a wide and partly overlapping energy range, the single-electron capture cross-sections for collisions of metastable Sn2+(5s5p Po3) (Sn2+∗) ions with H2 molecules were measured (0.1–10 keV) and calculated (0.3–1000 keV). The semi-classical calculations use a close-coupling method on a basis of electronic wavefunctions of the (SnH2)2+ system. The experimental cross-sections were extracted from double collisions in a crossed-beam experiment of Sn3+ with H2. The measured capture cross-sections for Sn2+∗ show good agreement with the calculations between 2 and 10 keV, but increase toward lower energies, whereas the calculations decrease. Additional Landau–Zener calculations were performed and show that the inclusion of spin-orbit splitting cannot explain the large cross-sections at the lowest energies which we now assume to be likely due to vibrational effects in the molecular hydrogen target

Strongly anisotropic ion emission in the expansion of Nd:YAG-laser-produced plasma

We present results from a combined experimental and numerical simulation study of the anisotropy of the expansion of a laser-produced plasma into vacuum. Plasma is generated by nanosecond Nd:YAG laser pulse impact (laser wavelength λ = 1.064 μ m) onto tin microdroplets. Simultaneous measurements of ion kinetic energy distributions at seven angles with respect to the direction of the laser beam reveal strong anisotropic emission characteristics, in close agreement with the predictions of two-dimensional radiation-hydrodynamic simulations. Angle-resolved ion spectral measurements are further shown to provide an accurate prediction of the plasma propulsion of the laser-impacted droplet