Correlation expansion: a powerful alternative multiple scattering calculation method.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Multiple scattering (MS) calculations are crucial for understanding electron scattering in materials.
• Standard MS series expansions can diverge at low energies and require significant computational resources.
• Existing methods face challenges in near-edge regions and with large atomic clusters.

Purpose of the Study:

• To introduce a novel correlation expansion method for multiple scattering calculations.
• To address the limitations of standard MS series expansions, including divergence and computational cost.
• To provide a general framework for calculating scattering path operator matrix elements.

Main Methods:

• Developed a correlation expansion that partitions scattering processes by small atom groups.
• Implemented the method for photoelectron diffraction calculations.
• Compared the correlation expansion against full MS and standard MS series expansions for a 23-atom cluster.

Main Results:

• The correlation expansion converges at all energies, unlike standard MS series.
• It demonstrates faster convergence than standard MS when the latter is convergent.
• The method requires less memory, enabling calculations in the near-edge region without divergence for large clusters.

Conclusions:

• The correlation expansion is a powerful and versatile alternative for multiple scattering calculations.
• It overcomes the low-energy divergence and high memory requirements of traditional MS methods.
• This approach facilitates accurate calculations for complex systems and in critical energy regimes.