The structural and dynamical properties of NO3- in dilute aqueous solution have been investigated by means of two combined quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulations, namely HF/MM and B3LYP/MM, in which the ion and its surrounding water molecules were treated at HF and B3LYP levels of accuracy, respectively, using the DZV+ basis set. On the basis of both HF and...

some of the adamantane properties were calculated in this study. chemical shift, free energy ofsolvation, free energy of cavity formation, henry's law constant, and other properties ofadamantane in dry phase, three solvents and three temperatures have been calculated with abinitio method base on density functional theory (dft) at b3lyp/6-31g, b31yp/6-31g*, b3lyp/6-31+g* and b3lyp/6-31++g** leve...

density-functional-based and ab initio calculations were implemented at different computational levels to estimate the binding energy of zn2+ ion adsorbed on the available sites of a silicate mel-type adsorbent. b3lyp and mp2 were used in combination with the 6-31g*, 6-31+g*, lanl2dz, 6-311+g*, and def2-tzvp basis sets. the zinc cation was found to preferentially occupy the 6mr sites followed b...

The geometries and relative energies of 3t-pentyl-2r,6c-diphenyl/di(thiophen-2-yl)piperidin-4ones (PIPs) and their oxime derivatives (PIPOXIs) have been investigated. The structural and spectroscopic analyses of PIPs and PIPOXIs were made by using B3LYP level with 6-311G(d,p) basis set. The optimized parameters show that the piperidi-4-one ring adopts chair conformation. Observed chemical shift...

Density functional calculations were used to explore the complexation of 3-alkyl-4-phenylacetylamino-4,5-dihydro-1h-1,2,4-triazol-5-one (ADPHT) derivatives by first-row transition metal cations. Neutral ADPHT ligand and mono deprotonated ligands have been used. Geometry optimizations have been performed in gas-phase and solution-phase (water, benzene, and N,N-dimethylformamide (DMF)) with B3LYP...

We perform a systematic examination on the dependence of the calculated nuclear magnetic shielding constants on the chosen geometry for a selective set of density functional methods of B3LYP, PBE0, and OPBE. We find that the OPBE exchange-correlation functional performs remarkably well when either the optimized geometries or the experimental geometries are used. The popular B3LYP and PBE0 funct...

The ground and excited state geometries, the excitation and emission energies for a series of fluorescein derivatives in aqueous solutions have been investigated using time-dependent density functional theory (TD-DFT) with B3LYP and a long-range corrected CAM-B3LYP functional. The RI-CC2 method was employed to confirm the CAM-B3LYP results. As far as we know, the excited state geometries for a ...

Ab initio quantum chemical calculations, G3B3, second-order Møller– Plesset (MP2), and the hybrid density functional method B3LYP were employed to compute the proton affinities of 24 heterocyclic amines. A range of basis sets are employed, starting from doublepolarization quality to triplequality basis set with augmented diffuse and polarization function. Experimental values were used to calibr...