Ab initio Calculations of Copper Nanostructures of MgO Substrate

2004 ◽  
Vol 99-100 ◽  
pp. 219-222
Author(s):  
O. Sychev ◽  
Y.F. Zhukovskii ◽  
Eugene A. Kotomin ◽  
G. Borstel
Keyword(s):  
Computer Simulation ◽  
Ab Initio ◽  
Physical Adsorption ◽  
Computer Code ◽  
Adhesion Energy ◽  
Slab Model ◽  
Dominant Contribution ◽  
Multipole Moments ◽  
Densities Of States ◽  
Mgo Substrate

Ab initio slab simulations were performed for copper adhesion to a perfect MgO(001) surface using the DFT-LCGTF method as implemented in CRYSTAL98 computer code. In order to clarify the nature of interfacial bonding, we considered a slab model of the Cu/MgO(001) interface with regular 1/4 monolayer (ML), 1/2 ML, 1 ML and 2 ML substrate coverages and verified the results of our calculations. In particular, the dependences of the adhesion energy per Cu atom, projections of multipole moments as well as total and projected densities of states (DOS) on the substrate coverage by a metal are analyzed. Computer simulation indicated that physical adsorption makes the dominant contribution to bonding on the regular Cu/MgO(001) interface.

Atomic and Electronic Structure of the Corundum (0001) Surface

1996 ◽  
Vol 453 ◽  
Author(s):  
V. E. Puchin ◽  
E. A. Kotomin ◽  
A. L. Shluger
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Basal Plane ◽  
Strong Dependence ◽  
Photoelectron Spectra ◽  
Slab Model ◽  
Hartree Fock ◽  
Electron Spectra ◽  
Densities Of States ◽  
Atomic And Electronic Structure

AbstractThe electronic structure and geometry of the Al terminated corundum (0001) surface were studied using a slab model within the ab-initio Hartree-Fock technique. The distance between the top Al plane and the next O basal plane is found to be considerably reduced on relaxation (by 0.57 Å, i.e. by 68% of the corresponding interlayer distance in the bulk). An interpretation of experimental photoelectron spectra (UPS Hel) and metastable impact electron spectra (MIES) is given. Calculated projected densities of states exhibit a strong dependence on the relaxation of surface atoms.

The effect of blob size in polymer networks on nanoparticle-mediated adhesion of hydrogels

Soft Matter ◽  
2019 ◽  
Vol 15 (48) ◽  
pp. 9942-9948
Author(s):  
Sohyun Kim ◽  
Tae Hui Kang ◽  
Gi-Ra Yi
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Pore Diameter ◽  
Physical Adsorption ◽  
Mesoporous Silica Nanoparticles ◽  
Polymer Networks ◽  
Mesh Size ◽  
Adhesion Energy ◽  
Polymer Chains

Mesoporous silica nanoparticles can be used as an adhesive for hydrogels due to their physical adsorption to polymer chains, in which adhesion energy can be affected by the ratio of mesh size and pore diameter.

Ab initio study of structural, electronic, and thermal properties of Pt1−xPdx alloys

2017 ◽  
Vol 31 (01) ◽  
pp. 1650243 ◽  
Author(s):  
Shabbir Ahmed ◽  
Muhammad Zafar ◽  
M. Shakil ◽  
M. A. Choudhary ◽  
Muhammad Raza-Ur-Rehman Hashmi
Keyword(s):  
Thermal Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Harmonic Approximation ◽  
Linear Response Theory ◽  
Potential Method ◽  
Lattice Constants ◽  
Debye Temperatures ◽  
Density Functional Perturbation Theory ◽  
Densities Of States

We report a systematic theoretical study of Pt[Formula: see text]Pd[Formula: see text] alloys using ab initio density functional theory (DFT) by pseudo potential method. We have used super cell approach to investigate structural, electronic and thermal properties of Platinum (Pt), Palladium (Pd) and their alloys Pt[Formula: see text]Pd[Formula: see text]([Formula: see text] = 0.00, 0.25, 0.50, 0.75, 1.00). The calculated lattice constants and bulk moduli are in good agreement with available literature data. The results of electronic properties revealed that the alloys are metallic in nature. The thermal properties were investigated through density functional perturbation theory (DFPT) and quasi-harmonic approximation. The contribution to the free energy from the lattice vibration was calculated using the phonon densities of states (DOS) derived by means of the linear-response theory. The DFPT with quasi-harmonic approximation methods was applied to determine the phonon DOS and thermal quantities i.e., the Debye temperatures, vibration energy, entropy and constant-volume specific heat.

M CENTER DIFFUSION, EXCITONS AND ADSORPTIVITY OF ATOMIC H AND He ON LiH (001) SURFACE: ab initio STUDY

2000 ◽  
Vol 11 (08) ◽  
pp. 1491-1507 ◽  
Author(s):  
A. S. SHALABI ◽  
KH. M. EID ◽  
M. A. KAMEL ◽  
Z. M. FATHI
Keyword(s):  
Ab Initio ◽  
Physical Adsorption ◽  
Band Gaps ◽  
Cluster Method ◽  
Surface Relaxation ◽  
Singlet Ground State ◽  
Spin Pairing ◽  
Homo And Lumo ◽  
Bulk Relaxation ◽  
Moller Plesset

An attempt has been made to examine the energetic properties of M center diffusion, excitons near M 2+, M +, M, M - and M 2- centers and adsorptivity of atomic H and He over defect free and defect containing surfaces of LiH using an ab initio embedded cluster method at the Hatrtree–Fock approximation and Moller–Plesset second order perturbation correction. The results confirm the following, (1) the calculated barriers to diffusion of M center in its lowest triplet excited state is always greater than those in its singlet ground state; (2) the triplet M center is not produced directly by optical processes, but, indirectly by thermal diffusion; (3) the exclusive dependence of exciton bands and the nonexclusive dependence of band gaps on the defect charge; (4) surface relaxation is not more important than bulk relaxation; (5) the M center changes the nature of H adsorption from physical adsorption to chemical adsorption; (6) bulk or surface M 2- changes the nature of LiH from an insulator to a semiconductor; (7) as M center is introduced, the HOMO and LUMO levels of the substrate shift to higher energies and band gaps become narrower. This change in the electronic structure makes charge transfer between adsorbate and substrate levels and spin pairing with atomic H more facile.

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