In the present work a conformational analysis of pindolol, a beta-blocker, is performed using several computational methods, including HF, DFT (B3LYP) and MP2. The relative electronic energies as well as the relevant dihedral angles of the significant conformer geometries are reported. At the HF and DFT levels the most stable conformers of pindolol are characterized by an extended backbone stru...

Using electronic structure calculations, we conduct an extensive investigation into the Hf-Ta-C system, which includes the compounds that have the highest melting points known to date. We identify three major chemical factors that contribute to the high melting temperatures. Based on these factors, we propose a class of materials that may possess even higher melting temperatures and explore it ...

We have performed CCSD(T), MP2, and DF-LMP2 calculations of the interaction energy of CO on the MgF(2)(110) surface by applying the method of increments and an embedded cluster model. In addition, we performed periodic HF, B3LYP, and DF-LMP2 calculations and compare them to the cluster results. The incremental CCSD(T) calculations predict an interaction energy of E(int) = -0.37 eV with a C-down...

The thermodynamic functions such as enthalpy (H), Gibbs free energy (G) and entropy (S) of Serineand Threonine amino acids were theoretically studied at different condition (solvents andtemperatures) by using Gussian o3, software. First, the structural optimization of isolated Serine andThreonine were done in the gas phase by using the Hartree-Fock (HF) level of theory with 3-21G, 6-31G and 6-3...

In this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational IR spectra of the tautomers were   investigated at HF and B3LYP level using the AB initio 6-31G* and LANL2DZ basis sets from the program package Gaussian 98 (A.7 Public Domain version). The physico-chemical and biochemical properties of uracil and cytosine are one of...

Reaction resonances are transiently trapped quantum states along the reaction coordinate in the transition state region of a chemical reaction that could have profound effects on the dynamics of the reaction. Obtaining an accurate reaction potential that holds these reaction resonance states and eventually modeling quantitatively the reaction resonance dynamics is still a great challenge. Up to...

The purpose of this work is to predict elastic and thermodynamic properties of Cr-based alloys based on first-principles calculations and to demonstrate an appropriate computational approach to develop new materials for high-temperature applications in energy systems. In this study, we choose Poisson’s ratio as screening parameter for identifying ductilizing additives to the refractory alloys. ...

At germanium/high-k interfaces cations and oxygen interstitials can diffuse into the germanium substrate. Here we employ density functional theory calculations to investigate the interaction of a range of such cations (Al, Y, Zr, Nb, La, and Hf) with intrinsic defects and oxygen in germanium. It is predicted that high-k cations strongly bind with lattice vacancies, oxygen interstitials, and A-c...

Dedicated to Prof. Dr. R oland Köster on the occasion o f his 60th birthday Z. Naturforsch. 39b, 1053-1057 (1984); received March 20, 1984 Topological-effect-on-molecular-orbitals (TEMO) theorem, ab initio Calculations, Dibora-diazarines Minimal STO-NG (N = 3, 4 and 6 ) basis set non-empirical HF SCF MO calculations have been performed for topologically related l,4-dibora-2,3-diazarine (S) and ...

The breathing-mode giant monopole resonance (GMR) is studied within the framework of the relativistic mean-field theory using the Generator Coordinate Method (GCM). The constrained incompressibility and the excitation energy of isoscalar giant monopole states are obtained for finite nuclei with various sets of Lagrangian parameters. A comparison is made with the results of nonrelativistic const...