arXiv subjects

K. Doll

Publications and source records attributed to K. Doll.

24 records · Page 2Linked to original sources

arXiv2001

Density functional study of the adsorption of K on the Cu(111) surface

The adsorption of potassium on the Cu(111) surface in a 2x2 pattern has been simulated with all-electron full-potential density functional calculations. The top site is found to be the preferred adsorption site, with the other highly symmetric adsorption sites being nearly degenerate. The bond length from potassium to the nearest copper atom is computed to be 2.83 Angstrom. Population analysis and density of states indicate that there is no evidence for covalent bonding so that the binding mechanism appears to be a metallic bond.

cond-mat.mtrl-sci↗

arXiv2001

Implementation of analytical Hartree-Fock gradients for periodic systems

We describe the implementation of analytical Hartree-Fock gradients for periodic systems in the code CRYSTAL, emphasizing the technical aspects of this task. The code is now capable of calculating analytical derivatives with respect to nuclear coordinates for systems periodic in 0, 1, 2 and 3 dimensions (i.e. molecules, polymers, slabs and solids). Both closed-shell restricted and unrestricted Hartree-Fock gradients have been implemented. A comparison with numerical derivatives shows that the forces are highly accurate.

physics.comp-ph↗

arXiv2001

Theoretical study of the chlorine adsorption on the Ag(111) surface

We study the adsorption of chlorine on the Ag(111) surface with full potential gradient corrected density functional calculations. When considering a root3 x root3 R30degree pattern, we find that the fcc hollow is the most favorable adsorption site. We obtain an Ag-Cl bond length of 2.62 Angstrom which is intermediate between two controversial experimental results. We discuss the differences of core level energies and densities of states for the different adsorption sites. We find the Cl-Ag interaction to be more consistent with an ionic, rather than covalent, picture of the bonding. In addition, we compute energetics and related properties of Ag bulk and the clean Ag surface comparing the local density approximation and the generalized gradient approximation.

cond-mat.mtrl-sci↗

arXiv2000

Analytical Hartree-Fock gradients for periodic systems

We present the theory of analytical Hartree-Fock gradients for periodic systems as implemented in the code CRYSTAL. We demonstrate how derivatives of the integrals can be computed with the McMurchie-Davidson algorithm. Highly accurate gradients with respect to nuclear coordinates are obtained for systems periodic in 0,1,2 or 3 dimensions.

cond-mat.mtrl-sci↗

arXiv1999

Chlorine adsorption on the Cu(111) surface

We investigate the adsorption of chlorine on the Cu(111) surface with full potential all-electron density functional calculations. Chlorine adsorption at the fcc hollow sites is slightly preferred over that at the hcp hollow. The adsorption geometry is in excellent agreement with electron diffraction and ion scattering data. Adsorption energies and surface diffusion barriers are close to those deduced from experiment.

cond-mat.mtrl-sci↗

arXiv1999

A density functional study of lithium bulk and surfaces

We report the bulk and surface properties of lithium computed within a full potential LCGTO formalism using both density functional theory and the Hartree-Fock approximation. We examine the convergence of computed properties with respect to numerical approximations and also explore the use of finite temperature density functional theory. We demonstrate that fully converged calculations reproduce cohesive properties, elastic constants, band structure, and surface energies in full agreement with experimental data and, where available, previous calculations.

cond-mat.mtrl-sci↗