Silicon AD-Dimer Binding on Si(100)

1995 ◽  
Vol 389 ◽  
Author(s):  
Peter J. Bedrossian ◽  
Arthur P. Smith ◽  
Hannes Jonsson
Keyword(s):  
Ab Initio ◽  
Local Density Approximation ◽  
Room Temperature ◽  
Local Density ◽  
Density Approximation ◽  
Tunneling Microscopy ◽  
Gradient Correction

ABSTRACTIsolated Si ad-dimers nucleate predominantly on Si(100) substrate dimer rows at room temperature. Using tunneling microscopy (STM), we find that, while ad-dimers oscillate between two mutually orthogonal orientations, the geometry with the ad-dimer bond perpendicular to the substrate's dimer bonds is the more stable. This observation confirms a prediction of ab initio calculations with a gradient correction for the energies of ad-dimers in various configurations, which differs from that of the local density approximation (LDA).

Elastic constants of polycrystalline Al and TiN calculated by an ab initiomethod within the local-density approximation

2001 ◽  
Vol 16 (8) ◽  
pp. 2293-2297
Author(s):  
Ming Zhang ◽  
Jiang Shen ◽  
Jiawen He
Keyword(s):  
Density Functional Theory ◽  
Single Crystal ◽  
Ab Initio ◽  
Elastic Constants ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Functional Theory ◽  
Cubic Materials

The three single-crystal elastic constants of the cubic materials Al and TiN were calculated by an ab initio method within the local-density approximation of density-functional theory. The values were compared with experiment and averaged by the Kroner method to give polycrystalline results. The results agree well with experiment.

Ab initio total energy studies of minerals using density functional theory and the local density approximation

1995 ◽  
Vol 59 (397) ◽  
pp. 589-596 ◽  
Author(s):  
Björn Winkler ◽  
Victor Milman ◽  
Michael C. Payne
Keyword(s):  
Total Energy ◽  
Ab Initio ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Lattice Energy ◽  
Density Approximation ◽  
Proton Proton ◽  
Energy Calculations ◽  
Good Agreement

AbstractAb initio total energy calculations based on the local density approximation (LDA) and using a conjugate-gradient solver for the Kohn-Sham equations have been performed for cordierite, brucite, (Mg(OH)2) and diaspore (AlOOH). The calculated fractional coordinates of all structures are in good agreement with experimental diffraction data. The angle of the non-linear hydrogen bond in diaspore is reproduced well. The Raman active OH stretching frequency in brucite has been calculated using the frozen phonon approach and the calculated stretching frequency is in very good agreement with the observed value. The energetically most favourable calculated orientation of the proton-proton vector of an H2O molecule incorporated in the structural channels of cordierite agrees with findings deduced from spectroscopic data, and the calculated energy of hydration is in reasonable agreement with calorimetric data. It is therefore concluded that ab initio total energy calculations can confidently be used to predict properties of hydrogen bonded structures, which is difficult with conventional parameterized static lattice energy minimization calculations. An extension to the model is necessary to improve the agreement of the predicted to the observed lattice parameters for small structures.

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