What is it about?
In this study, a new method based on self-consistent field theory for ring polymers is applied to predict the behaviour of neutral atoms hydrogen to neon in their ground states, modelling the Pauli-exclusion principle as excluded volume between these polymers. The model predicts the emergence of an atomic shell structure and spontaneous spherical symmetry-breaking of the total electron density. The origin of this symmetry breaking is explained using a technique from self-consistent field theory, where we find that the electrons break spherical symmetry to get closer to the nucleus and lower the atomic binding energy. The model also shows excellent agreement with Hartree-Fock theory for the atomic binding energies and density profiles of the first six elements, and the plots of pair densities display behaviour similar to polymer macro-phase separation.
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Why is it important?
In this paper, we use a new framework for density functional theory that we developed to explain the mechanism underlying spontaneous spherical symmetry-breaking in ground-state atoms and a newly constructed computational method to provide full angular electron density distributions. Within the framework the electrons are divided into pairs, predicting novel structures for these electron pair distributions which we can make sense of using our framework plus a specialized decomposition of the binding energy. This is significant because to our knowledge, the reason for spherical symmetry-breaking has not been explicitly elucidated before, nor have there been any previous reports of the electron pair structures shown in our paper.
Perspectives
This work demonstrates how techniques from polymer physics can help to understand and model quantum systems, which I hope will both promote cross-disciplinary research and help to promote alternative perspectives on quantum systems from a classical point of view. The paper was a lot of fun to write and even more so to discuss with my coauthor, and I hope you find it interesting as well.
Phil LeMaitre
University of Waterloo
Read the Original
This page is a summary of: On the Origins of Spontaneous Spherical Symmetry-Breaking in Open-Shell Atoms Through Polymer Self-Consistent Field Theory, The Journal of Chemical Physics, January 2023, American Institute of Physics,
DOI: 10.1063/5.0131364.
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