Biomedical subjects

Gerald Geudtner

Publications and source records attributed to Gerald Geudtner.

3 recordsLinked to original sources

PubMed2006

Parallelization of the deMon2k code.

The parallelization of the LCGTO-KS-DFT code deMon2k is presented. The parallelization of the three-center electron repulsion integrals, the numerical integration using a direct grid algorithm and the matrix multiplication and diagonalization are described. The efficiency of the parallelization is analyzed by selected benchmark calculations. It is shown that geometry optimizations of systems with more than 8,000 basis functions are feasible on cluster architectures.

Algorithms↗

PubMed2005

Separation of sigma and pi energies.

This work presents an all-electron density functional theory implementation of the separation of sigma and pi energies. On the basis of the separation of the electronic density, rho, into sigma and pi parts, an ansatz for the separation of the exchange-correlation energy is proposed. The behavior of the sigma and pi energy parts in benzene is investigated under different distortions. The effect of local and nonlocal functionals on the separation of the exchange-correlation energy is studied, too.

Journal Article↗

PubMed2003

Bond energies for molecules, clusters, and deposit systems.

A new approach is suggested to the assignment of bond energies in molecules and clusters. It uses a shareholder principle for the redistribution of the shifts in atomic energies, which arise in a molecule, on the bonds. The scheme is directly suitable for semiempirical methods, where only one- and two-center terms occur. MSINDO calculations are performed to demonstrate the suitability of the approach for molecules and clusters. As an application the bonding in a deposit system is analyzed for the case of copper on magnesium oxide. It is found that copper atoms do not only bind to the preferred oxygen sites but also substantially to the magnesium sites. The copper-copper bonds are the strongest and will determine the structure of copper clusters on magnesium oxide surfaces.

Journal Article↗