Article
Hydrography and circulation in the Northern Gulf of California during winter of 1994-1995
Fecha
2011Autor
Rodriguez-Zavala, J.G.
Barajas-Barraza, R.E.
Padilla-Osuna, I.
Guirado-Lopez, R.A.
Institución
Resumen
We have performed semi-empirical as well as density functional theory calculations in order to analyse the hydration properties of both bare C 60 and highly hydroxylated C60(OH)26 fullerenes. In all of our calculations, a total of 42 and 98 water molecules are always surrounding our here-considered carbon nanostructures. We found different wetting properties as a function of the chemical composition and structure of the OH-molecular over-layer covering the fullerene surface. In the case of bare C60, water adsorption reveals that the H2O species are not uniformly arranged around the carbon network but rather forms water droplets of different sizes, clearly revealing the hydrophobic nature of the C60 structure. In contrast, in the polyhydroxylated C 60(OH)26 fullerenes, the degree of wetting is strongly influenced by the precise location of the hydroxyl groups. We found that different adsorbed configurations for the OH-molecular coating can lead to the formation of partially hydrated or completely covered C60(OH) 26 compounds, a result that could be used to synthesize fullerene materials with different degrees of wettability. By comparing the relative stability of our hydroxylated structures in both bare and hydrated conditions we obtain that the energy ordering of the C60(OH)26 isomers can change in the presence of water. The radial distribution function of our hydrated fullerenes reveals that water near these kinds of surfaces is densely packed. In fact, by counting the number of H2O molecules which are adsorbed, by means of hydrogen bonds, to the surface of our more stable C 60(OH)26 isomer, we found that it varies in the range of 5-10, in good agreement with experiments. Finally, by comparing the calculated optical absorption spectra of various C60(OH)26 structures in the presence and absence of water molecules, we note that only slight variations in the position and intensity of the electronic excitations are found, indicating that their vacuum optical properties are more or less preserved in aqueous environments. " 2011 IOP Publishing Ltd.",,,,,,"10.1088/0953-4075/44/20/205104",,,"http://hdl.handle.net/20.500.12104/41995","http://www.scopus.com/inward/record.url?eid=2-s2.0-80053517097&partnerID=40&md5=7f7c05312f802364086e56987a5e6f9b",,,,,,"20",,"Journal of Physics B: Atomic, Molecular and Optical Physics",,,,"44",,"Scopus WOS",,,,,,,,,,,,"Hydration behaviour of polyhydroxylated fullerenes",,"Article"
"43782","123456789/35008",,"Palacios-Hernández, E., Universidad de Guadalajara, Departamento de Física, Guadalajara, Jalisco, Mexico; Carrillo, L., El Colegio de la Frontera Sur, Chetumal, Quintana Roo, Mexico; Lavín, M.F., CICESE, Departamento de Oceanografía Física, Ensenada, Baja California, Mexico; Zamudio, L., Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, FL, United States; García-Sandoval, A., Universidad de Guadalajara, Departamento de Física, Guadalajara, Jalisco, Mexico",,"Palacios-Hernandez, E. Carrillo, L. Lavin, M.F. Zamudio, L. García-Sandoval, A.",,"2006",,"Hydrographic and current measurements in the Northern Gulf of California from December 1994 through March 1995 show conditions that are markedly different from those accepted as typical for winter. A rapid subsurface warm water intrusion (?0.5°C warmer) was observed, which reduced the stratification and stopped, and eventually reversed the typical anticyclonic winter circulation. An empirical orthogonal function analysis of the mean vertical structure of temperature and salinity of historical hydrographic data reveals that similar conditions occurred during March 1973 (warm water intrusion and weakening of stratification). In this study, it is proposed that these anomalous conditions are due to a combination of local and remote forcings: extensive water-mass formation in the Upper Gulf of California and the arrival of an intraseasonal downwelling coastally trapped wave to the Northern Gulf of California. " 2005 Elsevier Ltd. All rights reserved.