scholarly journals Jellium surface energy beyond the local-density approximation: Self-consistent-field calculations

2001 ◽  
Vol 63 (4) ◽  
Author(s):  
J. Pitarke ◽  
A. Eguiluz
Keyword(s):  
Surface Energy ◽  
Local Density Approximation ◽  
Local Density ◽  
Density Approximation ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

Self-consistent-field calculations of atoms and ions using a modified local-density approximation

1994 ◽  
Vol 50 (1) ◽  
pp. 171-176 ◽  
Author(s):  
David A. Liberman ◽  
James R. Albritton ◽  
Brian G. Wilson ◽  
William E. Alley
Keyword(s):  
Local Density Approximation ◽  
Local Density ◽  
Density Approximation ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

scholarly journals Self-Consistent Field Modeling of Pulling a Test-Chain away from or Pushing It into a Polymer Adsorption Layer

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1684 ◽  
Author(s):  
Fransicus A.M. Leermakers
Keyword(s):  
Adsorption Layer ◽  
Local Density ◽  
Polymer Concentration ◽  
Critical Force ◽  
Average Chain Length ◽  
Single Chain ◽  
Field Modeling ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

We consider single chain force measurements to unravel characteristics of polymers at interfaces and to determine parameters that control adsorption or probe layer characteristics that are difficult to access otherwise. The idea is to have at the tip of an atomic force microscope (AFM), a probe chain and measure its behaviour near interfaces by pushing it to, or pulling it away from it. The self-consistent field modeling of this reveals that in the pulling mode—i.e., when the chain has an affinity for the surface—a typically inhomogeneous flower-like conformation forms with an adsorbed ’pancake’ and a stretched stem (tether) from the surface to the tip of the AFM. When about half the segments is in the tether it snaps loose in a first-order like fashion. The critical distance of the end-point from the surface and the critical force are experimentally accessible. Details of this transition depend on the surrounding of the test chain. Inversely, and this opens up many possibilities, the test chain reports about its surroundings. Our focus is on the classical case of homopolymers at interfaces. Pulling experiments may reveal the adsorption strength, the (average) chain length and/or the polymer concentration of the freely dispersed/adsorbed polymers. When the test-chain is non-adsorbing we envision that pushing this test-chain into the adsorption layer reports about various layer characteristics such as the layer thickness and (local) density. Moreover, when the test-chain has a length longer than the entanglement length, we can imagine that non-trivial dynamical properties of loops and tails may be scrutinised.

CHEMISORPTION OF O2 AND CO ON COPPER CLUSTERS

1996 ◽  
Vol 03 (01) ◽  
pp. 687-693 ◽  
Author(s):  
HENRIK GRÖNBECK ◽  
ARNE ROSÉN
Keyword(s):  
Charge Transfer ◽  
Local Density Approximation ◽  
Size Dependence ◽  
Local Density ◽  
Wave Functions ◽  
Density Approximation ◽  
Copper Clusters ◽  
Self Consistent ◽  
Stable Product ◽  
Transfer Mechanisms

The initial chemisorption of O 2 and CO on small copper clusters in the range from six to nine atoms has been investigated using a self-consistent jellium description of the clusters. The calculations were performed within the local-density approximation expanding the wave functions in a linear combination of atomic and spherical jellium orbitals. The results indicate a strong size dependence in the chemisorption energies. O 2 was found to be most strongly bound to the Cu 9 cluster while COCu 6 was the most stable product in the case of CO chemisorption. The observations are consistent with experiments and the underlying reasons were traced to differences in cluster-adsorbate hybridization and charge-transfer mechanisms.

Embedded Atom Model of Surface Stress and Early Film Growth in Electrodeposition: Ag/Au(111)

1996 ◽  
Vol 451 ◽  
Author(s):  
Michael I. Haftel ◽  
Nervine Rosen ◽  
Sean G. Corcoran
Keyword(s):  
Surface Energy ◽  
Electron Density ◽  
Surface Stress ◽  
Local Density Approximation ◽  
Film Growth ◽  
Local Density ◽  
Density Approximation ◽  
Atom Model ◽  
Embedded Atom ◽  
Electrolytic Potential

ABSTRACTWe develop an embedded-atom-model (EAM) for simulations of metallic film growth under electrodeposition. The surface charge induced by the electric field is handled as an addition to the electron density to be used in the EAM. Parameters relating the shift in electron density to the electrolytic potential are calibrated to measurements of the capacitance and of surface stress versus potential for Au. For Ag the calibration is to capacitance and local density approximation calculations of surface energy. The resulting parameters are physically realistic for the experiments performed. The model is then applied to calculating migration and step edge barriers for Ag electrodeposited on Au (111) as an explanation of the observed Stranski-Krastanov growth.

Sign in / Sign up

Export Citation Format

Share Document