Molecular Orbital Calculation
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Modelo molecular para o magnetismo em ferro, cobalto e nÃquel
We have proposed a molecular model to magnetism in Fe, Co e Ni. To we carried through molecular orbital ab initio calculations using the density functionals UB3LYP, UBLYP, UBHLYP, UBP86, UBP386, UB3PW91, PBE1PBE e LSDA. We, also use the methods UHF, CIS and MP4. The basis used were 6-311G(d,p), LanL2DZ e LanL1mb. The computacional calculations mention the st
Publicado em: 2009
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2. "Dusty Plasmas: stellar winds and the interstellar medium" / "Plasmas empoeirados: ventos estelares e o meio interestelar"
In this work, we firstly discuss the propagation of Alfvén waves in dusty plasmas found in several astrophysical environments. The wave dispersion relation is modified giving rise to new damping mechanisms. There are in the literature observational data indicating the presence of dust near the surface of cool giant and supergiant stars. We developed a stell
Publicado em: 2005
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3. Reações de 1,1,1-tricloro-4-metoxi-3-penten-2-ona com hidrazinas monosubstituídas / 1,1,1-trichloro-4-methoxy-3-penten-2-ona reaction with hydrazines
The 1,1,1-trichloro-4-methoxy-3-penten-2-ona (CCl3COCH=CHOMe) reaction with hydrazines series (RNHNH2, where R = H, Me, tert-Bu, Ph, Ph(F)5, Ph-4-NO2, CO2Me e CONH2) yield to the pyrazoles N-substituted and derivatives formation by [3 + 2] ciclocondensations reactions. These compounds formation is regioespecific, it means, termodinamically controled (excepti
Publicado em: 2005
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4. AplicaÃÃes de metodologias teÃricas em estudos de QSAR-3D de pirimidinas substituÃdas
The aim of this work is determining a 3D QSAR model for a homologous series of substituted pyrimidines with known anti-inflammatory activities. Previous results from classic QSAR (which include AM1 calculated parameters) have shown the importance of electronic parameters in the successful prediction of a novel and more active compound. The first step was to
Publicado em: 2004
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5. Um modelo molecular para o magnetismo em ferro, cobalto e nÃquel
The orbital angular moment and the angular moment of spin guarantee the magnetism of the substance. When treating, specifically, of the magnetism in the iron, cobalt and nickel we are admired for the complexity that these metals of transition present in its referring electronic distributions to its levels of valence. Literature registers that many electronic
Publicado em: 2003
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6. Estudos em estruturas e reatividade de reações Sn2
The gas phase reactions of the HO, NC and HCC anions with the methyl fluoride by the bimolecular nucleofilic substitution mechanism (SN2) was caracterized by ab initio calculations using basis sets of (9s6p1d/4s1p) [4s3p1d/2s1p] leveI. Eletronic correlation energy was included using up to fourth order MøIIer-Plesset perturbation theory. The importance of sp
Publicado em: 1992
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7. Estudos de ressonancia magnetica nuclear de 2-metilpropenos 3-substituidos
The aim of the present work has been the investigation of the substituent effects in the Carbon-13 and Hydrogen-1 chemical shifts of some 3-substituted 2-methylpropenes ( I ), which bear a closely related geometry to a -substitued propanones. The following compounds (I) have been obtained in good yields. through usual methods where changes were introduced ei
Publicado em: 1987
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8. Configuration Interaction in the Calculation of Oscillatory and Rotatory Intensities of Nonplanar π-Electronic Systems
The interaction of configurations, including all possible singly excited configurations, is incorporated into the calculation of oscillatory and rotatory intensities of simple nonplanar π-electronic systems such as skewed butadiene and acrolein. The results are discussed in terms of the reliability of the (self-consistent field)-(linear combination of atomi
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9. Charge calculations in molecular mechanics 6: the calculation of partial atomic charges in nucleic acid bases and the electrostatic contribution to DNA base pairing.
A previously described scheme for the direct calculation of the partial atomic charges in molecules (CHARGE2) is applied to the nucleic acid bases. It is shown that inclusion of the omega-technique for the calculation of HMO derived pi charges is of particular importance for these highly polar systems. The molecular dipole moments obtained for the resulting
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10. The Pairwise Correlated Generalized Valence Bond Model of Electronic Structure I; The Estimation of Pair Energies from Orbital Overlaps
A new method for the accurate a priori calculation of atomic and molecular energies is proposed. The new method agrees with experiment to within less than 1 kcal/mole in all cases examined thus far, and is applicable to excited states and to transition states for chemical reactions. Since the new method corrects the results of generalized valence bond calcul
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11. Structural mimicry of adenosine by the antitumor agents 4-methoxy- and 4-amino-8-(beta-D-ribofuranosylamino)pyrimido[5,4-d]pyrimidine as viewed by a molecular modeling method.
A rationale for the antitumor activity of 4-methoxy- and 4-amino-8-(beta-D-ribofuranosylamino)pyrimido-[5,4-d]pyrimidine (beta-MRPP and beta-ARPP, respectively) was studied by a molecular modeling method. Although these nucleoside analogues are structurally different from adenosine, they act as substrates for adenosine kinase. The molecular modeling method,