Structural properties of Na adsorbed on a Ge(100)2 × 1 surface: all electron, ab initio, density functional, cluster calculations

In this paper we report the results of calculations of the energies associated with the segregation of boron on the [Formula: see text] surface. These calculations have been carried out using the plane wave pseudopotential density functional code fhi98md in a periodic slab formalism. The segregation energy is predicted to be -0.77 eV. This prediction is intermediate between the "experimentally determined" values of -0.33 eV and -0.48 eV, and the values of -1.83 eV and -2.10 eV determined from AM1 cluster calculations. Additional information has been obtained by performing ab initio density functional cluster calculations using the Gaussian98 code. These latter results indicate that the AM1 calculations significantly overestimate the segregation energy of boron on the [Formula: see text] surface. They also provide strong support for the fhi98md calculations.

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Tuning Electronic and Structural Properties of Triple Layers of Intercalated Graphene and Hexagonal Boron Nitride: An Ab-initio Study.

MRS Proceedings ◽

10.1557/opl.2011.364 ◽

2011 ◽

Vol 1307 ◽

Author(s):

Samir S. Coutinho ◽

David L. Azevedo ◽

Douglas S. Galvão

Keyword(s):

Boron Nitride ◽

Electric Field ◽

Ab Initio ◽

Band Gap ◽

External Electric Field ◽

Structural Properties ◽

Density Functional ◽

Hexagonal Boron Nitride ◽

Electronic And Structural Properties ◽

Gap Values

ABSTRACTRecently, several experiments and theoretical studies demonstrated the possibility of tuning or modulating band gap values of nanostructures composed of bi-layer graphene, bi-layer hexagonal boron-nitride (BN) and hetero-layer combinations. These triple layers systems present several possibilities of stacking. In this work we report an ab initio (within the formalism of density functional theory (DFT)) study of structural and electronic properties of some of these stacked configurations. We observe that an applied external electric field can alter the electronic and structural properties of these systems. With the same value of the applied electric field the band gap values can be increased or decreased, depending on the layer stacking sequences. Strong geometrical deformations were observed. These results show that the application of an external electric field perpendicular to the stacked layers can effectively be used to modulate their inter-layer distances and/or their band gap values.

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Prediction of Thermodynamic and Structural Properties of Sulfamerazine and Sulfamethazine in Water Using DFT and ab Initio Methods

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v62i1.575 ◽

2018 ◽

Vol 62 (1) ◽

Cited By ~ 1

Author(s):

Neda Hazhir ◽

Farhoush Kiani ◽

Hasan Tahermansouri ◽

Saraei Ghorbani-Hasan Azade ◽

Fardad Koohyar

Keyword(s):

Ab Initio ◽

Structural Properties ◽

Density Functional ◽

Ionization Constant ◽

Intermolecular Hydrogen Bond ◽

Research Work ◽

Dft Methods ◽

Polarized Continuum Model ◽

Acid Ionization Constant ◽

Acid Ionization

The acid-ionization constant (pK<sub>a</sub>) is an important physico-chemical property of molecules. In this research work, the ab initio and density functional theory (DFT) methods, in combination with the polarized continuum model (PCM), were used to calculate the acid-ionization constant of sulfamethazine (SMZ) and sulfamerazine (SMR) solved in water. For these molecules, the calculated pK<sub>a</sub> value is in relatively good agreement with the experimental one. Also, in these calculations some structural properties such as dihedral angle between the indicated atoms: D, bond lengths between the indicated atoms: d, Bohr radius: a˳, intermolecular hydrogen bond: IHB, and total atomic charge: au have been determined. These data can be used in nano drug modeling of sulfamethazine and sulfamerazine.

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