Search results for "POLARIZABILITY"

Origin of Kerr effect: investigation of solutions by polarization dependent Z-scan

2020

This material is based upon work supported by the ERDF 1.1.1.1 activity project No. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices”.

Effect of type, size and deformation on the polarizability of carbon nanotubes from atomic increments

2006

The interacting induced dipole polarization model is used for the calculation of the dipole–dipole polarizability α. The method is tested with single-wall carbon nanotubes (SWNTs) as a function of nanotube radius and elliptical deformation. The results are similar to ab initio reference calculations. For the zigzag tubes, the polarizability follows a remarkably simple law. The calculations effectively differentiate among SWNTs with increasing radial deformations. The polarizability and related properties can be modified continuously and reversibly by the external radial deformation. These results suggest a technology in which mechanical deformation can control chemical properties of the car…

Intramolecular charge delocalization and nonlinear optical properties of Methyl 3-(4-methoxy phenyl) prop-2-enoate from vibrational spectra

2005

The density functional computations of MMP are performed at B3LYP/6-31G (d,p) level to derive equilibrium geometry, vibrational wavenumbers and intensities, and first hyperpolarizability. Large NLO efficiency predicted for the first time in this new class of compounds has been confirmed by powder efficiency experiments. DFT calculation reveals that endocyclic angle at the junction of the propenoate group and the phenyl ring is decreased from 120° by 2.5°, whereas two neighbouring angles around the ring are increased by 2.1° and 1.2° respectively, associated with intramolecular charge transfer interaction. The vibrational spectra confirm the charge transfer interaction between -COOCH3 group…

Graphene and Fullenene Clusters

2017

Interacting induced-dipoles polarization in code POLAR permits calculating molecular polarizability, which is tested with endohedral metallofullerenes Scn@Cm and clusters Cn (fullerene, graphene, GR). Polarizability identifies aggregates with dissimilar numbers of atoms and separates isomers. Results are of the same order of magnitude as reference computations performed with code PAPID. Polarizability bulk limit is estimated from Clausius–Mossotti relationship. Polarizability trend for clusters vs. size is unexpected: they are more polarizable than bulk. Theory yielded the same for small Sin, Gen and GanAsm; however, experiment oppositely deferred for larger Sin, GanAsm and GenTem. Smaller …

Frequency-Dependent Dielectric Polarizability of Flexible Polyelectrolytes in Electrolyte Solution: A Dissipative Particle Dynamics Simulation

2019

Molecular-mediated assembly of silver nanoparticles with controlled interparticle spacing and chain length

2012

In the present work, we report on a one-pot method for the assembly of noble metal nanoparticles with tunable optical properties, assembly length and interparticle spacing. The synthetic colloidal route is based on the covalent binding among OH-terminated silver nanoparticles by means of dicarboxylic acids with a defined molecular length. As a result, the initially symmetric plasmon band of silver nanoparticles splits into two plasmonic modes when nanoparticles are assembled due to the strong near-field plasmon coupling. We noticed a very good correlation between the plasmon wavelength shift and the interparticle spacing that is represented by the universal scaling law of the surface plasmo…

Solvation parameters of solutes: an attempt of improvements in characterization and determination

2008

We are presenting here an updated version of our predictive model of solvation parameters of solutes, based on a simplified molecular topology (J. Chem. Inf. Model, 2006, 46, 1723-1734). The learning experimental database of this model is presently larger than in our first version and includes more compounds with more than one functional group of the same type. This experimental database is also surer, in the sense that it only includes compounds in liquid state at room temperature, when the polarizability of a compound in solution is established via its refractive index in gas or crys- talline state. Indeed, we demonstrate in this paper, a bias in this case.

Polymer based tuneable photonic crystals

2007

We report on the fabrication and characterization of photonic crystal slab waveguide resonators which contain a nanostructured second-order nonlinear optical polymer. The combination of a photonic crystal resonator realized in a second-order nonlinear optical polymer allowed the detection of electro-optical modulation of light with a sub-1-V sensitivity. Furthermore we report on the synthesis of novel nonlinear optical polymers with large second-order hyperpolarizability and improved glass transition temperature. The polymer slab waveguide is micro patterned by means of electron-beam lithography and reactive ion etching. The photonic crystal slab-based resonator consisted of a square lattic…

Plasmonic Silver Nanorod Sensitivity: Experiment and Simple Theoretical Treatment

2013

We compare the plasmonic sensitivity of silver and gold nanorods with similar resonance wavelengths by monitoring the plasmon resonance shift of single noble metal nanorods upon changing the environment from water to sucrose solution. We find that silver nanorods have 1.2 to 2 times higher sensitivity than gold in good agreement with simulations based on the boundary-elements-method (BEM). To exclude the effect of particle volume on sensitivity, we test gold rods with increasing particle width at a given resonance wavelength. Using the Drude-model of optical properties of metal together with the quasi-static approximation (QSA) for localized surface plas-mons, we show that the dominant cont…

Electronic polarizability of small sodium clusters.

1986

Abstract : Small sodium clusters consisting of 1 to 40 atoms are described as spheres of interacting homogeneous electron gas (jellium model). The static electronic polarizability is calculated using self consistent density functional methods. An excellent agreement with recent experimental results is observed.