Encontrados 8 documentos, a visualizar página 1 de 1
Analysis of natural and artificial ultramarine blue pigments using laser induce...
Osticioli, I.; Mendes, N. F. C.; Nevin, A.; Gil, Francisco P. S. C.; Becucci, M.; Castellucci, E.http://www.sciencedirect.com/science/article/B6VNG-4V2NKN2-1/2/88334c7b5f21f6ac19eed9f3f8706b02
Dynamics of muoniated radical states in phthalocyanines
Piroto Duarte, J.; Vilão, R. C.; Alberto, H. V.; Gil, J. M.; Gil, Francisco P. S. C.; Weidinger, A.; Campos, N. Ayres deThis work reports a spectroscopic and spin-dynamics [mu]SR study of the positive muon states formed in the phthalocyanines Zn-Pc, H2-Pc and Cu-Pc. In Zn-Pc and H2-Pc, three distinct muoniated radicals are formed, seen to undergo spin-dynamical processes with charge carriers. Two of the states have very similar hyperfine interaction values, and are believed to be due to muon addition at the outer benzene rings. ...
Solvent effects on 2-methoxyethanol conformers: an ab initio DFT study using th...
Gil, Francisco P. S. C.; Teixeira-Dias, J. J. C.The four stable conformers of 2-methoxyethanol, CH3O-CH2-CH2-OH (tgg', ggg', ttg and ttt) are studied by ab initio calculations using the SCRF theory and the SCI-PCModel to assess solvent effects on the structure and vibrational spectra of this compound. Full geometry optimizations were carried out at the B3LYP/6-311+G(3df,2df,2p)//B3LYP/6-31G(d) level, and normal mode calculations were performed within the har...
Hydrogen-Bonded Dimers of CH3OCH2CH2OH: Ab Initio Structures and Multivariate A...
Gil, Francisco P. S. C.; Costa, A. M. Amorim da; Bruns, Roy E.; Teixeira-Dias, J. J. C.Structures and vibrational frequencies of relevant hydrogen-bonded dimers of 2-methoxyethanol are obtained at the 3-21G*//Ah41 level (the 3-21G* basis set included polarization functions deliberately added to second period atoms) and the results analyzed by standard multivariate methods. Dimers built from the same pair of isolated monomers belong to the same homologous series. The most stable dimer is obtained ...
Conformational Analysis of CmH2m+1OCH2CH2OH (m = 1-4): The Role of CH.cntdot..c...
Gil, Francisco P. S. C.; Costa, A. M. Amorim da; Teixeira-Dias, J. J. C.Structures and energies of the more stable conformations of C ~ H ~ ~ + I O C H ~ C(HCm~EOl, Hm = 1-4) have been determined by gradient geometry refinement at ab initio level. For m = 3 (C~EIa)n d m = 4 (C~EI )t,h e results show that attractive CH-O intramolecular interactions associated with the formation of five-membered rings in the alkylic fragments of these molecules lead to the stabilization of gauche arr...
Oxygen-by-Sulfur Substitution in CH3OCH2CH2OH: An Ab Initio Comparative Study o...
Gil, Francisco P. S. C.; Costa, A. M. Amorim da; Teixeira-Dias, J. J. C.Conformational energies, structural parameters and vibrational frequencies for the tgg’, ggg’, ttg, and ttt conformers of CH~XCH~CHZY(XH, Y = 0, S) have been determined by MO ab initio calculations at the MP2/6-31G* level. The results show that the relative strength of the intramolecular X. *HY interaction in tgg’ and ggg‘ conformers diminishes gradually along the series of molecules (0,O) - (0,s) - (S,O) - (S,...
Structures and Vibrational Spectra of CH,OCH,CH,OH : The
Gil, Francisco P. S. C.; Fausto, R.; Costa, A. M. Amorim da; Teixeira-Dias, J. J. C.Ab initio calculations at the MP2/6-31G* and MP2/6-31G*//6-31G* levels have been carried out for the monomer of 2-methoxyethanol (CH,OCH,CH,OH). The MP2/6-31G* results indicate that the two more stable conformers (tGg’ and gGg‘) display intramolecular hydrogen bonds directed from the hydroxy H atom to one of the lone pairs of the ether 0 atom, and that the tGg’ conformer is 6.3 kJ mol-’ more stable than the gGg...
Conformers, Vibrational Spectra and Laser-induced Rotamerization
Fausto, Rui; Teixeira-Dias, Jose J. C.; Gil, Francisco P. S. C.A6 initio molecular orbital (MO) calculations with a 6-31G* basis set have been carried out for CH,CICOOH. Structures and energies of relevant conformations have been determined by gradient geometry refinement and some conformationally dependent geometry trends discussed. The results agree with reported experimental data and provide a good insight for the intramolecular interactions which determine the relative...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||