0000000000223871
AUTHOR
Dorothee Richters
showing 4 related works from this author
Liquid methane at extreme temperature and pressure: Implications for models of Uranus and Neptune
2012
We present large scale electronic structure based molecular dynamics simulations of liquid methane at planetary conditions. In particular, we address the controversy of whether or not the interior of Uranus and Neptune consists of diamond. In our simulations we find no evidence for the formation of diamond, but rather sp2-bonded polymeric carbon. Furthermore, we predict that at high tem- perature hydrogen may exist in its monoatomic and metallic state. The implications of our finding for the planetary models of Uranus and Neptune are in detail discussed.
Self-consistent field theory based molecular dynamics with linear system-size scaling
2012
We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented …
A General Algorithm to Calculate the Inverse Principal $p$-th Root of Symmetric Positive Definite Matrices
2019
We address the general mathematical problem of computing the inverse p-th root of a given matrix in an efficient way. A new method to construct iteration functions that allow calculating arbitrary p-th roots and their inverses of symmetric positive definite matrices is presented. We show that the order of convergence is at least quadratic and that adaptively adjusting a parameter q always leads to an even faster convergence. In this way, a better performance than with previously known iteration schemes is achieved. The efficiency of the iterative functions is demonstrated for various matrices with different densities, condition numbers and spectral radii.
Linear-scaling self-consistent field theory based molecular dynamics: application to C60buckyballs colliding with graphite
2018
In this work, we investigate the collision of a C fullerene with graphite using large-scale molecular dynamics simulations, where the interatomic forces are computed ‘on-the-fly’ by means of self-c...