Clean and As covered zinc-blende and wurtzite GaN surfaces have been investigated employing density-functional theory calculations. For clean GaN surfaces our calculations indicate the stability of several novel surface structures that are very different from those found on traditional III-V semiconductors. Adding impurities commonly present in significant concentrations during growth strongly ...

where r is the distance between covalently bonded atoms , a is the corresponding equilibrium distance, and ka is the spring constant. The equilibrium distance between atoms can be obtained from X-ray diffraction experiments or using ab initio quantum calculations. The spring constant can be determined using the results of infrared adsorption and Raman spectroscopy. The frequency of bond length ...

Barium isotopes could be a novel tracer in low-temperature geochemical processes such as the Ba cycle rivers and oceans. Equilibrium isotope fractionation between Ba-hosting minerals aqueous solution is of great importance for applications geochemistry, but it remains poorly constrained. In this study, we performed first-principles calculations based on density functional theory (DFT) to determ...

a theoretical study of the kinetic and mechanism of 3-aug-cope rearrangement in gas phase was performed usingdet methods at b3lyp levels of theory with 6-3114ig(d,p) bass set at 298.i5k. equilibrium moleculargeometries and harmonic vibrational frequencies of the reactant, transition state did product were calculated. then,rate constant and activation thermodynamics parameters were calculated an...

a theoretical study of the kinetics and mechanism of second-order intermolecular c.) cloadd it ion of 2-ethyny1-2,3-dihydrofurane and phenyl azide was performed using dft method at 101.111 le) cl of theory with 6-31 preg(d,p) basis set at 298.15k. equilibrium molecular geometries and harmonic ) ihrational frequencies ofthe reactants, transition state, and product were calculated. the kinetic an...