We introduce a semiempirical method to correct the systematic equilibrium lattice parameters underestimation present in first principles calculations based on the local density approximation. The method consists in performing calculations under a negative pressure such that the calculated equilibrium volume matches the experimentally observed one. We find that elastic properties obtained under ...

Economic and financial processes are complex and highly nonlinear. However, somewhat surprisingly, linear models like ARMAXGARCH often describe these processes reasonably well. In this paper, we provide a possible explanation for the empirical success of these models. 1 Formulation of the Problem Economic and financial processes are very complex. It is well know that economic and financial proc...

We describe a semiempirical method for constructing pseudopotentials for use in correlated wave-function calculations which involves using a combination of calculated and experimental quantities. The pseudopotentials are generated from single-valence-electron configurations and satisfy a norm-conservation condition. Core relaxation and core-polarization effects are taken into account. Detailed ...

Semiempirical calculations at the level of PM3 of theory were carried out to study the structural and electronic properties of C80 and some of its doped derivatives with the elements of group III and V at the level of PM3 of theory. We have selected these elements to be substituted in the fullereneC80 cage in order to show the effect of such structural change on the electronic properties of the...

introduction: solar net radiation (rn) is one of the most important component which influences soil heat flux, evapotranspiration rate and hydrological cycle. this parameter (rn) is measured based on the difference between downward and upward shortwave (sw) and longwave (lw) irradiances reaching the earth’s surface. field measurements of rn are scarce, expensive and difficult due to the instrum...

für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

Theoretical available values of thermal conductivity are commonly different from the experimentally obtained values. In the present work, a thermodynamic system has been considered and variations in temperature in different elements were analyzed and corresponding thermal conductivities were calculated. These values were compared and the corrected values were justified on the basis of a mathema...

The conformational structure of a series of 2,4-disubstituted pentanes (substituents F, Cl, Br, I, CN, CH3, H) has been calculated, taking account of three types of interactions: dispersion interactions, dipole-dipole interactions, and the three-fold barrier of the C-C bond. Dihedral angles have been adjusted so as to attain the local potential energy minimum for each conformer. The results of ...

We apply a semiempirical R-matrix theory to calculations of vibrational excitation and dissociative attachment in the CF3Cl molecule for electron energies below about 3 eV. We employ two sets of model parameters corresponding to two different forms of the CF3Cl − potential curve. We fi nd that our present, ab initio calculated anion curve gives vibrational excitation and dissociative attachment...