Eudes E. Fileti

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Sequential Monte Carlo/Quantum Mechanical calculations of the interaction energy of hydrogen-bonded methanol in liquid water gives the same result for methanol acting either as the proton donor or the proton acceptor. For the complex-optimized cases methanol acting as the proton acceptor, CH3HO· · ·H2O, is more stable than the proton donor, CH3OH· · ·OH2,(More)
Hydrogen binding energies are calculated for the different isomers of 1:1 complexes of methanol, ethanol and water using ab initio methods from MP2 to CCSD(T). Zero-point energy vibration and counterpoise corrections are considered and electron correlation effects are analyzed. In methanol–water and ethanol–water the most stable heterodimer is the one where(More)
Combined Metropolis Monte Carlo computer simulation and first-principles quantum mechanical calculations of pyridine in water are performed to analyze the role of thermal disorder in the electronic properties of hydrogen bonds in an aqueous environment. The simulation uses the NVT ensemble and includes one pyridine and 400 water molecules. Using a very(More)
Ab initio calculations of depolarization ratios and intensities of classically scattered light, in terms of dipole polarizabilities and polarizability anisotropies, are reported for different hydrogen bonded molecular clusters. Five different groups of organic heterodimers formed with water are considered: HCHO · · ·H2O, CH3HO · · ·H2O, HCOOH · · ·H2O,(More)
Molecular dynamics simulations were used to predict the thermodynamical properties of the hydration process of the adamantane, diamantane, and trimantane, the first three members of the series of diamondoids. Free-energy results suggest that the water solubility of these molecules is low. The hydration free energy increases with size of the diamondoid. As(More)
We investigate the impact of hydroxyl groups on the properties of C(60)(OH)(n) systems, with n = 1, 2, 3, 4, 8, 10, 16, 18, 24, 32 and 36 by means of first-principles density functional theory calculations. A detailed analysis from the local density of states has shown that adsorbed OH groups can induce dangling bonds in specific carbon atoms around the(More)
Diverse atomistic parameters of C60 have been developed and utilized to simulate fullerene solutions in biological environments. However, no thermodynamic assessment and validation of these parameters have been so far realized. Here, we employ extensive molecular dynamics simulations with the thermodynamic integration method in the isothermal-isobaric(More)
In this work we present the results for hyperpolarizabilities of the methanol molecule including vibrational corrections and electron correlation effects at the CCSD level. Comparisons to random phase approximation results previously reported show that the electron correlation is in general important for both electronic contribution and vibrational(More)
Isotropic and anisotropic chemical shifts for all atoms of complexes CH3HO . . . H2O and CH3OH . . . OH2 have been calculated at the Hartree–Fock, secondorder Møller-Plesset (MP2) and density functional (B3LYP) theoretical levels using the 6-311 G(2d,2p) basis set. The influence of the hydrogen bond formation on the nuclear magnetic resonance chemical(More)
Ab initio calculations at the B3LYP/aug-cc-pVDZ, B3PW91/aug-ccpVDZ, MP2/aug-cc-pVDZ, B3LYP/6-311 G(2d,2p), B3PW91/6-311 G(2d,2p), and MP2/6-311 G(2d,2p) levels are performed for the IR spectra of isolated water and methanol molecules and hydrogen-bonded water–methanol, methanol–water, and methanol–methanol complexes. Frequency shifts and changes in(More)