Research

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Applications for Modelling of Ions

3D Extended MHD simulation of fusion plasmas. NERSC Fusion Energy Sciences, SciDAC Projects Center for Extended Magnetohydrodynamic Modeling (CEMM).

Full 3D numerical simulation of plasma particle drift orbits in a tokamak. NIMROD project, funded by the DOE Office of Fusion Energy Sciences and the SciDAC, Center for Extended Magnetohydrodynamic Modeling.

Related Links

Donald R. Beck Faculty Page

Beck Research Website

Physics Computational Facilities

Professor of Physics Donald R. Beck, Postdoctoral Research Associate Steven O'Malley and graduate student Lin Pan predict properties of rare earth negative ions and transition metal positive ions. These open f-shell (open d-shell) ions are very difficult to treat, as they require the simultaneous inclusion of relativity and correlation. Many negative ions would not exist “without” electron correlation. Energy matrices of order 100,000 or more may be needed.

Many of the atomic species are found little changed in technologically important solid environments too. Applications include plasma fusion (effect of impurities on operation), catalysis, magnets, astrophysical abundances, nuclear waste, atomic clocks, and advanced lighting sources. The work has received long term funding from NSF and DOE.

Beck Group Current Projects

1. Photoionization cross sections for Ce^-.

   We predicted several bound states for this ion (see Beck publications), which has only recently been measured. Experimental analysis has been limited to date due to the lack of photoionization cross sections. No fully relativistic-well correlated “first principles” cross sections of any rare earth ions currently exist. Our work will include such effects.

2. Wavelengths for transitions within the 4f⁷ levels of Gd IV (3+).

   This ion may be a “lasing” defect in PbF₂ (see work of Pandey Group alumnus H. Jiang) and is also of interest to Atomic Parity Non-Conservation studies (weak neutral currents in the nucleus). No “first principles” calculation existed for these wavelengths, prior to our current work. The calculations have been too difficult to undertake previously. We are seeking to reduce energy difference errors to below 0.1 eV for this very complicated ion.

3. Energy levels and transition probablities for Mo VI (5+).

   Although this ion may appear to have a simple Na I-like spectra, it does not. The 4p⁵ 4d² levels interpenetrate the 4p⁶ nl levels, requiring a “meticulous” treatment of electron correlation. Specifically, there is less cancellation of correlation effects than normal; i.e. more electrons must be explicitly correlated. A consistent set of experimental results is also lacking.