نتایج جستجو برای: polarizability

تعداد نتایج: 2621  

Journal: :Physical review letters 2015
Konrad Piszczatowski Mariusz Puchalski Jacek Komasa Bogumił Jeziorski Krzysztof Szalewicz

Future metrology standards will be partly based on physical quantities computed from first principles rather than measured. In particular, a new pressure standard can be established if the dynamic polarizability of helium can be determined from theory with an uncertainty smaller than 0.2 ppm. We present calculations of the frequency-dependent part of this quantity including relativistic effects...

2008
Andrei Alexandru Frank X. Lee

The background field method has been used successfully to determine hadron electromagnetic polarizabilities. Recently questions have been raised regarding the proper way to deal with the electric field on the lattice. In this paper, we show how the presence of a background electric field affects the quark hopping matrix. We use this formulation to carry out simulations on quenched configuration...

Journal: :Molecules 2017
Chen Chen Nan Gong Zuowei Li Chenglin Sun Zhiwei Men

Absorption, fluorescence spectra of chlorophyll a (Chl-a) and all-trans-β-carotene (β-Car) mixing solution are investigated in different polarity and polarizability solvents. The carotenoids regulate the energy flow in photosynthesis by interaction with chlorophyll, leading to an observable reduction of Chl-a fluorescence. The fluorescence red shifts with the increasing solvent polarizability. ...

Journal: :The Journal of chemical physics 2015
Bing-Sui Lu Ali Naji Rudolf Podgornik

We analyze van der Waals interactions between two rigid polymers with sequence-specific, anisotropic polarizabilities along the polymer backbones, so that the dipole moments fluctuate parallel to the polymer backbones. Assuming that each polymer has a quenched-in polarizability sequence which reflects, for example, the polynucleotide sequence of a double-stranded DNA molecule, we study the van ...

2008
Lucia Hackermüller Klaus Hornberger Stefan Gerlich Michael Gring Hendrik Ulbricht Markus Arndt

We discuss a novel application of matter wave interferometry to characterize the scalar optical polarizability of molecules at 532nm. The interferometer presented here consists of two material absorptive gratings and one central optical phase grating. The interaction of the molecules with the standing light wave is determined by the optical dipole force and is therefore directly dependent on th...

Journal: :Physical chemistry chemical physics : PCCP 2015
Alejandro Morales-Bayuelo Sudip Pan Julio Caballero Pratim K Chattaraj

The validity of maximum hardness, minimum electrophilicity and minimum polarizability principles is assessed to explain the phenomenon of torquoselectivity (inward and outward preference) in the conrotatory ring opening reactions of trans-3,4-dimethylcyclobutene into Z,Z- and E,E-butadienes and 3-formylcyclobutene into E- and Z-2,4-pentadienals. The hardness, average polarizability and electrop...

2009
K. Slifer

JLab has been at the forefront of a program to measure the nucleon spin-dependent structure functions over a wide kinematic range, and data of unprecedented quality has been extracted in all three experimental halls. Moments of these quantities have proven to be powerful tools to test QCD sum rules and provide benchmark tests of Lattice QCD and Chiral Perturbation Theory. Precision measurements...

2006
Henrik Wallén Ari Sihvola

The classical electrostatic problem of two nonintersecting conducting spheres in a uniform incident electric field is considered. Starting from the basic Kelvin’s image principle, the two spheres are replaced with equivalent series of image sources, from which the polarizability is calculated. Explicit expressions for the axial and transversal components of the polarizability dyadic are found b...

Journal: :Optics letters 2000
P C Chaumet M Nieto-Vesperinas

We establish the time-averaged total force on a subwavelength-sized particle in a time-harmonic-varying field. Our analysis is not restricted to the spatial dependence of the incident field. We discuss the addition of the radiative reaction term to the polarizability to deal correctly with the scattering force. As an illustration, we assess the degree of accuracy of several previously establish...

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