Excitation transfer scattering

The first term furnishes the differential cross section of direct elastic scattering, and the second term that of excitation transfer scattering. With this approximation... 

Using this model they have tried to look at important chemical processes at metal surfaces to deduce the role of electronic nonadiabaticity. In particular, they have tried to evaluate the importance of electron-hole-pair excitation in scattering, sticking and surface mobility of CO on a Cu(100) surface.36,37 Those studies indicated that the magnitude of energy transferred by coupling to the electron bath was significantly less than that coupled to phonons. Thus the role of electron-hole-pair excitation in... 

Our experiments are typically carried out at DNA concentrations of 20-50 /ig/ml with 1 ethidium per 300 bp, so that depolarization by excitation transfer is negligible.(18) The sample is excited with 575-nm light, and the fluorescence is detected at 630, 640, or 645 nm. Less than one fluorescent photon is detected for every 100 laser shots. The instrument response function e(t) is determined using 575-nm incident light scattered from a suspension of polystyrene latex spheres. 

The branching ratio is 1 1000 in favor of the ground state. The beam is scattered from a second supersonic beam, and the electronically excited atoms are detected. As excitation transfer can occur during the collision (e.g., He + Ne— He + Ne ), a second quench lamp is sometimes installed in front of the detector, to enable study of the energy-transfer process separately. 

A similar peak at 0iab = 9O° was observed by Martin et al.75 and by Haberland et al.76 in scattering studies of He + Ne. An interpretation similar to that for He -He was given first by the latter authors but was proven incorrect.75 The following two-step process is presently thought to be the most likely cause.77 An excitation transfer occurs from He (23S) to... 

In principle, there is no way to directly measure the exchange process for 4He +4He scattering, as the particles are indistinguishable. But the cross section for metastability exchange can of course be calculated from the determined potentials assuming distinguishable particles.65 The expression for the total excitation transfer cross section is... 

Scattering in Excitation-transfer Systems a. Elastic Scattering... 

Determination of macromolecules conformations is one of the basic problems of science about polymers. Simultaneously with development of theory [4-6] the perfection and enrichment of experimental methods of determination of macromolecules conformations in various phase and aggregate states occurs. However the method of neutron scattering was almost the only one method allowing reliable determination of polymer chains conformation in solid amorphous state until now [7], Not long ago they begun to use with this aim also the method based on measurement of rate of electron excitement transfer between molecules of chromophores covalent bonded with polymer chain [8],... 

The surface enhancement is ascribed to the occurrence of two separate effects, electromagnetic and chemical (70). The electromagnetic effect arises from small surface structures arising in the ORC that cause strong local increases of the electric fields of the excitation and scattered radiation via surface plasmon waves. The chemical effect is attributed to interactions between the adsorbed molecule and the metal surface which lead to electronic (charge-transfer) transitions between molecule and metal. The result is a res-onance-Raman-like effect. Since both effects operate only over very small distances, SERS is specific for molecules at the electrode surface. 

One of the advantages of classical mechanics is that it allows one to calculate any property of interest, since quantum mechanical constraints are absent classically one may know everything about a system. One can examine, in as much detail as one wishes, the behavior of the system at the atomic level. It is possible to calculate reaction rates, lifetimes of excited molecules, rates and probabilities of energy transfer, scattering distributions, the partitioning of energy among reaction products, the behavior of all the atoms as a function of time, and, in fact, any other classical property of a system. 

Marzocchi M P, Mantini A R, Casu M and Smulevich G 1997 Intramolecular hydrogen bonding and excited state proton transfer in hydroxyanthraquinones as studied by electronic spectra, resonance Raman scattering, and transform analysis J. Chem. Phys. 108 1-16... 

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