Electronic Structure Reading Group: Pseudopotentials

Following the fundamental idea of replacing the strong Coulomb potential of the atomic nuclei, altogether with the tightly bound core electrons, by an effective ionic potential binding only the valence electrons, pseudopotentials have been an invaluable tool in leveraging the computational cost of density functional theory calculations within plane-wave implementations.

In this talk, I will give an overview of pseudopotential generation schemes, focusing on norm-conserving and ultrasoft pseudopotentials. On one side, the norm-conserving construction introduced by Hamann, Schlüter and Chiang [1] constraints the pseudowavefunctions to give the same charge density of their all-electron counterparts,  allowing to build semilocal ab-initio pseudopotentials with good transferability properties.
On the other side, the ultrasoft scheme introduced by Vanderbilt [2] removes this constraint, allowing for a further reduction of the plane wave basis set, while simultaneously improving its transferability in a systematic way at the price of turning the eigenvalue problem into a generalized one.
Finally, I will also briefly discuss some relations between ultrasoft pseudopotentials and the projector augmented-wave method [3-4].

[1] D. R. Hamann, M. Schlüter and C. Chiang, Phys. Rev. Lett. 43, 1494 (1979)
[2] D. Vanderbilt, Phys. Rev. B 41, 7892(R) (1990)
[3] P. E. Blöchl, Phys. Rev. B 50, 17953 (1994)
[4] G. Kresse and D. Joubert, Phys. Rev. B, 1758 (1999)

This event is jointly organized with the COSMO seminar.
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The electronic structure reading group brings together researchers and students interested in mathematical aspects of electronic structure problems and adjacent topics, including:

• Density Functional Theory
• Many-body Schrödinger equation for electrons
• Born-Oppenheimer Molecular Dynamics
• Numerical analysis and error control