RÉPUBLIQUE FRANçAISE
CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE - COMMISSARIAT A L'ÉNERGIE ATOMIQUE
LABORATOIRE LÉON BRILLOUIN ( 33 (0) 1.69.08.52.41
Séminaire Physico-chimie & Biologie
Lundi, 6 Septembre 2004
14:30
Bât. 563 - salle 15
Dynamics of Adsorbed Hydrocarbons in Zeolite/Molecular Sieves: QENS Study
R. Mukhopadhyay
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
Zeolites are widely used as catalysts and molecular sieves. An understanding of the role of various factors in the molecular sieving characteristics could lead to tailor made, highly efficient molecular sieves. This is largely determined by the diffusivity of the guest molecules within the cavities of zeolites. The sorption, binding, and the transport characteristics of various adsorbates in zeolitic pore systems have been investigated extensively, both experimentally and theoretically, with an objective to achieve the fundamental understanding of the behavior of guest-molecules in confined geometries. It is also widely reported that the thermodynamic and transport properties of fluids are considerably altered on their physical confinement in well-defined channel and cavity system of porous materials. Here we will report Quasi Elastic Neutron Scattering (QENS) experiments investigating the role played by the symmetry and the structure of the guest molecule in addition to the physical characteristics of the sorbents. We have investigated various combinations of guest molecules and host structures, namely benzene, cyclohexane and methanol absorbed in HZSM-5 and MCM-41, propane and acetylene in Na-Y zeolite. It is found that the combination of pore size and structure vis-à-vis the size and shape of the guest molecules decides the dynamics. We shall also discuss some of the molecular dynamics simulation studies in the context of the QENS results.
L’accès au CEA Saclay est contrôlé, les chercheurs français et étrangers qui désirent assister à ces conférences sont invités à contacter C. Marais (0169085241), au moins deux jours avant la date du séminaire. À la porte Nord (accès par la route D36), ces personnes devront présenter une pièce d’identité prouvant leur nationalité et devront préciser qu’elles viennent assister au séminaire du LLB
Due to the restricted access to CEA Saclay, foreign scientists who wish to attend these seminars should call C. Marais (0169085241), at least two days prior to the date of the seminar. At the North entrance (D 36 road), these scientists will have to present a passport to prove their nationality and state that they will attend the seminar of the LLB.
Laboratoire Léon Brillouin - CEA/Saclay - F - 91191 GIF-SUR-YVETTE
Télécopieur 33 (0) 1.69.08.82.61