Clodoaldo Valverde

Synthesis, characterization, and third-order nonlinear optical properties of a new neolignane analogue

Recently, a wide number of pharmacological activities, such as anti-leishmanial, antioxidant and antitumor, have been discovered for neolignane analogues. To provide a view of the non-linear optical behavior of the third order of the crystal 2-(4-nitrophenoxy)-1-phenylethanone (NPH-PE) in the static and dynamic cases, we calculated its linear polarizability (α) and second hyperpolarizability (γ). We used a new supermolecule approach combined with an iterative electrostatic system whose atoms of the neighboring molecules are represented by point charges. A comprehensive investigation of NPH-PE is reported by single crystal X-ray diffraction and FT-Raman and NMR spectroscopy. In addition, a combination of density functional theory (DFT) with the CAM-B3LYP functional and the 6-311+G(d) basis set was used to calculate the molecular structure optimization, the vibrational frequencies, and the intensity of the vibrational bands. Concerning the values of the third-order optical nonlinearity, the second hyperpolarizability of the embedded molecule showed an increase of 125 058% in comparison with the corresponding result in the static case.

Synthesis, structural characterization and computational study of a novel amino chalcone: a potential nonlinear optical material

The interest for novel chalcone-based materials in nonlinear optics is dependent on strong second harmonic generation in organic systems. Chalcones are α,β-unsaturated ketones that can be easily obtained by Claisen–Schmidt condensation between ketones and aromatic aldehydes. A new 2-amino-chalcone was synthesized and its crystal molecular structure was elucidated using the single crystal X-ray diffraction technique. This compound, C15H12BrNO2, crystallizes in monoclinic centrosymmetric space group C2/c with cell parameters a = 29.47(7) A; b = 6.97(5) A, c = 13.59(1) A, β = 112.52(6)° and V = 2581.2(2) A3. In addition to the crystal structure, the analysis of Hirshfeld surfaces indicates the presence of hydrogen bonds of types N–H⋯O and O–H⋯O that stabilize two independent centrosymmetric dimers, and also indicates the presence of π–π stacking interactions that stabilize a supramolecular trimeric system. Being a push–pull chromophore we investigated the NLO properties of the 2-amino-chalcone asymmetric unit using the supermolecule approach in combination with an iterative electrostatic polarization scheme. The calculations were performed using the CAM-B3LYP/6-311+G(d) level of theory for both dynamic and static situations. In the presence of the embedding charges, the γ value is increased by 20% for the dynamic calculation but only 8% for the static limit. In contrast to the crystal form, when in solution the 2-amino-chalcone lacks an inversion center so that second order NLO properties do not vanish. Following this idea we computed the NLO properties using the implicit solvation approach IEF-PCM. The solvent effect on the NLO properties was to augment its values as the solvent polarity increases. We obtained for the in-crystal and in DMSO 2-amino-chalcone, γ(−2ω;ω,ω,0) = 144.12 × 10−36 esu and 260.163 × 10−36 esu, respectively, and therefore interesting materials for third order NLO applications.

Controlling Excitation Inversion of a Cooper Pair Box Interacting with a Nanomechanical Resonator

We investigate the action of time-dependent detunings upon the excitation inversion of a Cooper pair box interacting with a nanomechanical resonator. The method employs the Jaynes-Cummings model with damping, assuming different decay rates of the Cooper pair box and various fixed and time-dependent detunings. It is shown that, when the presence of damping plus constant detunings destroys the collapse/revival effects, convenient choices of time-dependent detunings allow one to reconstruct such events in a perfect way. It is also shown that the mean excitation of the nanomechanical resonator is more robust against damping of the Cooper pair box for convenient values of time-dependent detunings.

On the paradoxical evolution of the number of photons in a new model of interpolating Hamiltonians

We introduce a new Hamiltonian model which interpolates between the Jaynes-Cummings model and other types of such Hamiltonians. It works with two interpolating parameters, rather than one as traditional. Taking advantage of this greater degree of freedom, we can perform continuous interpolation between the various types of these Hamiltonians. As applications we discuss a paradox raised in literature and compare the time evolution of photon statistics obtained in the various interpolating models. The role played by the average excitation in these comparisons is also highlighted.

Solid state characterization and theoretical study of non-linear optical properties of a Fluoro-N-Acylhydrazide derivative

In this work we determine the linear and non-linear optical properties of a Fluoro-N-Acylhydrazide derivative (FBHZ), using a combined supermolecule approach and an iterative scheme of electrostatic polarization, where the atoms of neighbouring molecules are represented by point charges. Our results for non-linear optics (NLO) are comparable to those found experimentally, suggesting that FBHZ constitutes an attractive object for future studies and for use as an interesting material for third-order NLO applications. The dynamic electrical properties of FBHZ in different solvent media are reported. Its molecular properties are closely related to supramolecular features; accordingly, we analysed all its crystal structure properties via intermolecular interactions in the solid state, using X-ray crystallography data and Hirshfeld surface (HS), including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and hot-stage microscopy (HSM), where the results reveal crystal stability in respect to temperature variation.

The solid state structure and environmental polarization effect of a novel asymmetric azine

A broad analysis of a novel azine is reported using single crystal X-ray diffraction and characterization methods (IR, NMR and MS). Additional studies were conducted using density functional theory with the CAM-B3LYP functional and the 6-311+G(d) basis set, with the intention of calculating molecular structure optimization, vibrational frequencies, and the intensity of the vibrational bands. These results were seen to be in close agreement with those reported in the literature. Besides that, we determined the linear polarization (α) and the second hyperpolarizability (γ) of this new azine to understand its linear and nonlinear optical behaviour in both static and dynamic cases. A new supermolecule approach is employed, combined with an interactive electrostatic system in which the atoms of the neighbouring molecules are considered as point charges. The ab initio computational results of (hyper) polarizabilities derived from an iterative process confirm this crystal as a good candidate for photonic devices, such as optical switches, modulators, pyrazoline derivatives, and optical power applications. Besides that, we also calculated the effect of the solvent on the nonlinear optical properties of the title compound.

Hirshfeld Surfaces and Nonlinear Optics on Two Conformers of a Heterocyclic Chalcone

Heterocyclic chalcones have been prominent in the scientific community due to various biological activities reported for these compounds. The structural knowledge of heterocyclic chalcones can help in the understanding of their mechanism of action. The Hirshfeld surfaces were used to study the supramolecular arrangement of two conformers present into asymmetric unit of the heterocyclic chalcone (2E)-3-(4-methylphenyl)-1-(pyridin-3-yl)-prop-2-en-1-one on crystalline state. In addition, the linear polarizability (α), the first hyperpolarizability (β||z), and the second hyperpolarizability (γ) of the conformers were calculated to get a better insight on the linear and nonlinear optical behaviors of these structures in presence of solvent medium, as well as their band-gap energies. The Hirshfeld surfaces confirmed the presence of C−H···N, C−H···O and C−H···C interactions in packaging stabilization. Finally, the 2D fingeprint plot was used to the quantification of contacts and indicated that there are both π···π and C−H···π interactions present in the compound.

Statistical Properties of a System Consisting of a Superconducting Qubit Coupled to an Optical Field Inside a Transmission Line

The present work investigates the entropy and the excitation inversion of a coupled system that consists of a qubit represented by a Cooper pair box (CPB) interacting with a transmission line working as a circuit quantum electrodynamics (CQED). The proposed scheme uses the Buck-Sukumar model with a time dependent frequency in the presence of losses to study the evolution of the entropy and the excitation inversion of the system. We have shown that the CQED is much more sensitive to the presence of losses than the CPB. The results also show that it is possible to monitor properties of the subsystems through appropriate choices of the time-dependent parameters.