Correlation function quantum Monte Carlo calculations for ground and excited states of many-electron atoms and ions in neutron-star magnetic fields

• Applicant: Professor Dr. Günter Wunner
• Subject Area: Astrophysics and Astronomy
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 165331837

• Final Report Year: 2015

Final Report Abstract

On the methodological side, the goal of the project was to was to test and study the scope and power of the CF method in the calculation of atomic data in strong magnetic fields. For helium we could extend the range of magnetic field strengths accessible to the correlation function quantum Monte Carlo method by a factor of 10. The obstacle to going to yet higher field strengths was the growth of the variances with the field strength. This could be traced back to the fact that the energy difference between the bosonic and fermionic ground state grows with increasing field strength. Since these energy differences will be larger for higher elements, we had to conclude that the method is not extendible to higher elements. On the physical side our goal was to calculate energies and oscillator strengths of mid-Z elements in strong magnetic fields. This could be achieved by combining a two-dimensional Hartree-Fock-Roothaan method with a fixed-phase diffusion quantum Monte Carlo approach.

Publications

• Atomic ground states in strong magnetic fields: Electron configurations and energy levels, Phys. Rev. A, 88, 012509 (2013)
  Ch. Schimeczek, S. Boblest, D. Meyer, and G. Wunner
  (See online at https://doi.org/10.1103/PhysRevA.88.012509)
• Fixed-phase correlation-function Monte Carlo calculations for ground and excited states of helium in neutron-star magnetic fields. Phys. Rev. A, 87, 032515 (2013)
  D. Meyer, S. Boblest, and G. Wunner
  (See online at https://doi.org/10.1103/PhysRevA.87.032515)
• Ground states of helium to neon and their ions in strong magnetic fields. Phys. Rev. A, 89, 012505 (2014)
  S. Boblest, Ch. Schimeczek, and G. Wunner
  (See online at https://doi.org/10.1103/PhysRevA.89.012505)
• Multi-electron systems in strong magnetic fields I: The 2D Landau-Hartree-Fock-Roothaan method. Comput. Phys. Comm, 185, 2655–2662 (2014)
  Ch. Schimeczek and G. Wunner
  (See online at https://doi.org/10.1016/j.cpc.2014.05.005)
• Multi-electron systems in strong magnetic fields II: A fixed-phase diffusion quantum Monte-Carlo application based on trial functions from a Hartree-Fock-Roothaan method. Comput. Phys. Comm, 185, 2992–3000 (2014)
  S. Boblest, D. Meyer, and G. Wunner
  (See online at https://doi.org/10.1016/j.cpc.2014.06.027)