New routes to the interpretation of quasielastic neutron scattering spectra from proteins and other complex systems
Vendredi 13 janvier 2017 11:00
- Duree : 1 heure
Lieu : ILL 4, seminar room, 1st floor - 71 avenue des Martyrs - Grenoble
Orateur : Gerald KNELLER (Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, F-45071 Orléans, France & Synchroton SOLEIL, Saint Aubin - BP 48, F-91192 Gif-sur-Yvette CEDEX & Université d’Orléans, F-45067 Orléans, France)
Quasielastic neutron scattering (QENS) is a powerful technique for probing the atomic dynamics of proteins on time scales between roughly 1 picosecond and 100 nanoseconds. Many different types of motion are here superposed and the usual interpretation of QENS data in the framework of Van Hove’s theory is not appropriate, since it relies on a single dominant motion type. It also tacitly implies a complete disregard of recoil effects in the scattering of the neutrons by the sample.
In this talk two new routes to the interpretation of QENS spectra will be presented, which are both related to the qualitative concept of energy landscapes and which both describe recoil effects. The first one can be interpreted as a Franck-Condon theory of neutron scattering, where the neutrons “kick” the scattering system from one energy level to another. Here energy landscapes enter through transition matrix elements involving energy eigenfunctions of the scattering system in momentum space. The second one is based on the asymptotic form of the intermediate scattering function for long times, which reflects self-similarity and which is described by a few parameters only. Here the contact to energy landscapes can be made through an Arrhenius form of relaxation rate spectra. The practical meaning of “asymptotic” is discussed in this context.
Contact : martela@ill.fr
Discipline évènement : (Biologie / Chimie)
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Discipline évènement : (Physique)
Entité organisatrice : (ILL)
Nature évènement : (Séminaire)
Evènement répétitif : (General ILL Seminar - College 8)
Site de l'évènement : Polygone scientifique
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