The aromatic fluctuation index (FLU): a new aromaticity index based on electron delocalization

In this work, the aromatic fluctuation index (FLU) that describes the fluctuation of electronic charge between adjacent atoms in a given ring is introduced as a new aromaticity measure. This new electronic criterion of aromaticity is based on the fact that aromaticity is related to the cyclic delocalized circulation of π electrons. It is defined not only considering the amount of electron sharing between contiguous atoms, which should be substantial in aromatic molecules, but also taking into account the similarity of electron sharing between adjacent atoms. For a series of rings in 15 planar polycyclic aromatic hydrocarbons, we have found that, in general, FLU is strongly correlated with other widely used indicators of local aromaticity, such as the harmonic-oscillator model of aromaticity, the nucleus independent chemical shift, and the para-delocalization index (PDI). In contrast to PDI, the FLU index can be applied to study the aromaticity of rings with any number of members and it can be used to analyze both the local and global aromatic character of rings and molecules

Counterpoise-corrected geometries and harmonic frequencies of N-body clusters: application to (HF)n (n=3,4)

A study was conducted on the methods of basis set superposition error (BSSE)-free geometry optimization and frequency calculations in clusters larger than a dimer. In particular, three different counterpoise schemes were critically examined. It was shown that the counterpoise-corrected supermolecule energy can be easily obtained in all the cases by using the many-body partitioning of energy

Basin-scale hydrodynamics in a Mediterranean reservoir. Implications for the phytoplankton dynamics

Procesos hidrodinámicos determinan, en un alto grado la calidad del agua en embalse, sin embargo dichos procesos han sido tradicionalmente olvidados en la gestión de embalse. En esta tesis se presentan evidencias de los principales procesos hidrodinámicos que ocurren en un embalse Mediterráneo a escala de cuenca a través de campañas experimentales y modelización numérica; y su influencia en la dinámica de poblaciones de fitoplancton. Dichos procesos son principalmente la generación de ondas internas o secas y la intrusión del río. La presencia de viento periódico genera secas forzadas, amplificando los modos cercanos al periodo del viento, de manera que modos verticales altos, considerados como raros en la naturaleza, tienden a dominar en el sistema.