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DFT study of third-order nonlinear susceptibility of a chalcone crystal
The linear and nonlinear properties of a new chalcone derivative, (2E)-3-(3-methylphenyl)-1-(4-nitrophenyl)prop-2-en-1-one (3MPNP), have been investigated using an iterative electrostatic embedding scheme and density functional theory (DFT) methods with standard (B3LYP) and long-range corrected (CAM-B3LYP) functionals. There is a marked influence of electrostatic embedding on the dipole moment and second hyperpolarizability of the 3MPNP molecules in crystalline phase. CAM-B3LYP estimations of linear and nonlinear macroscopic quantities are in concordance with the available experimental results.
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 (JCM) 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 the photon statistics obtained in the various interpolating models. The role played by the average excitation in these comparisons is also highlighted.
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 (a) and the second hyperpolarizability (g) 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.
Theoretical study on the third-order nonlinear optical properties and structural characterization of 3-Acetyl-6-Bromocoumarin
Coumarin derivatives exist widely in nature and show a wide range of biological activities such as antiinflammatory, anti-oxidative and anti-cancer. The structure of C11H7BrO3 has been redetermined using 3330 measured reflections with 1666 unique [Rint = 0.0088] with final indices R1 = 0.0128 [I > 2r(I)] and wR2 = 0.0347 (all data). The bromocoumarin molecule is almost planar and has three planar dimers stabilized by interaction of type CAH Br and CAH O, which form parallel layers connected via several p–p interactions [centroid–centroid distances = 3.958(1) Å]. To provide a view of the non-linear optical behavior of third order of the crystal bromocoumarin in both cases static and dynamic, we calculate the linear polarizability ðaÞ and the second hyperpolarizability ðcÞ using a new supermolecule approach combined with an iterative electrostatic scheme where the neighboring molecules are represented by point charges. The results of calculations of the HOMO and LUMO energies show the occurrence of charge transfer inside the molecule. The computational results of the second (static and dynamics) hyperpolarizabilities show the molecule exhibiting second hyperpolarizability with values different of zero, which implies a third order microscopic behavior.