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Your search keyword '"Jessica Roman-Perez"' showing total 2 results
Start Over Author "Jessica Roman-Perez" Publisher american chemical society (acs)
2 results on '"Jessica Roman-Perez"'

1. Huge Energy Gain in Metal-to-Molecule Charge Transfer Processes: A Combined Effect of an Electrical Capacitive Enhancement in Nanometer-Size Hot Spots and the Electronic Structure of the Surface Complex

Author

S.P. Centeno, Juan F. Arenas, Cristina Ruano, Juan Soto, Jessica Roman-Perez, Juan C. Otero, and Isabel López-Tocón

Subjects
Chemistry, Capacitive sensing, Charge (physics), Electronic structure, Time-dependent density functional theory, Capacitance, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Metal, General Energy, visual_art, visual_art.visual_art_medium, Molecule, Physical and Theoretical Chemistry, Atomic physics, Electrode potential
Abstract

A comprehensive analysis of the effectiveness of the electrode potential (EV) in tuning the energies of the electronic states (E) of hybrid systems composed by molecules (A) bonded to discrete metal clusters (M) is carried out for the first time by combining experimental SERS data with TDDFT calculations on [Mn-A]q complexes of different sizes (n) and charges (q). It will be demonstrated that the unexplained origin of observed huge energy gains up to G = 5 eV/V involves two different contributions: G = ΔE/ΔEV = SC. The first one is responsible for the effect of a fractional charge (qeff = q/n) on the electronic structure of [Mn-A]q complexes which tunes the CT states through the slopes S of the E vs qeff diagrams. The second contribution (C = Δqeff/ΔEV) is a kind of capacitance that quantifies the ability of the metal to convert the electrode potential EV into the atomic excess of charge qeff. The estimated capacitances of nanometer-size SERS active hot spots are 2 or 3 times larger than those measured fr...

Published
2014

2. Franck–Condon Dominates the Surface-Enhanced Raman Scattering of 3-Methylpyridine: Propensity Rules of the Charge-Transfer Mechanism under Reduced Symmetry

Author

Isabel López-Tocón, Jessica Roman-Perez, Juan F. Arenas, Juan C. Otero, Juan Soto, and S.P. Centeno

Subjects
Physics, 3-Methylpyridine, Molecular physics, Spectral line, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Vibration, symbols.namesake, chemistry.chemical_compound, General Energy, chemistry, Computational chemistry, Transfer mechanism, symbols, Wavenumber, Molecule, Redistribution (chemistry), Physical and Theoretical Chemistry, Raman scattering
Abstract

The analysis of photoinduced charge transfer (CT) processes in a particular SERS spectrum is not a trivial task since each system must be studied separately and no universal selection rules can be proposed for this kind of enhancement mechanism. Despite this, we found out in previous studies that the SERS-CT spectra of benzene-like molecules are mainly characterized by the strong enhancement of the totally symmetric 8a ring-stretching vibration and we have used this as a propensity rule to recognize the presence of resonant CT processes in the SERS of these adsorbates. However, it is necessary to cautiously consider the relevant symmetry of the system under study before applying this simplified rule. When the molecule shows a low symmetry (or the relevant symmetry is reduced by the adsorption on the metal as it was demonstrated in the case of pyrimidine), the selective intensification of the 8a mode can be disguised by the redistribution of the CT enhancement with another close vibration in wavenumber, na...

Published
2012

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