the combination of quantum mechanics (qm) and molecular mechanics (mm) methods hasbecome alternative tool for many applications that pure qm and mm could not be suitable.the qm/mm method has been used for different type of problems, for example: structuralbiology, surface phenomena, and liquid phase. in this paper we have performed these methods forsome antibiotics and vitamins and then we comp...

The FT-IR and FT-Raman vibrational spectra of selegiline were recorded. The optimized geometry and wavenumbers in the ground state were calculated using density functional (B3LYP) method with standard 6-31G(d,p) basis set. The computed B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other methods. Natural bond orbital analysis of selegiline is also carried...

The strong sensitivity of the current flow between two ferromagnetic metals (FM’s) separated by a non-magnetic region to the relative orientation of their magnetization vectors is a fundammental physical phenomenon with a huge impact in the magneto-electronics industry[1]. The quantity characterizing this phenomenon is the so-called magneto-resistance (MR) which is defined as the difference in ...

Ab initio and DFT methods have been used to study the seven tautomeric forms of 5-methylcytosine molecule.The related tautomer in gas phase have been studied at HF/6-31G, HF/6-31G* and B3LYP/6-31G* levels oftheory. The structures,enthalpies,entropies,Gibbs free energies,relative tautomerization energies of tautomersand tautomeric equilibrium constants were compared and analyzed along with full ...

This contribution reports on the wavenumber shifts and linewidth changes observed for the Raman bands of the C-O and C-C stretching vibrations of tetrahydrofuran (THF) in a series of binary mixtures with water. Experimental results are compared with ab-initio calculations on THF and hydrogen-bonded THF-water complexes. The Raman spectroscopic analysis of vibrational relaxation processes such as...