Location of perdeuterated benzene sorbed at low pore-filling in a H·MFI material: A neutron powder diffraction study

Abstract

A synthetic H·MFI material presenting the H 1.30Al 1.30Si 94.70O 192 framework composition and containing 2.2C 6D 6 molecules sorbed at low pore-filling has been studied at room temperature by neutron powder diffraction (ILL, Grenoble, D2B diffractometer, λ = 2.4 A ̊ ). The experimental profile was analysed by combining profile-fitting structure refinements (Rietveld method with geometric restraints), interpretation of difference-Fourier maps and energy-minimization calculations using the atom-atom potential method (Buckingham model). At low pore-filling (<4 molecules/unit-cell), the deuterobenzene species are localized and disordered at the channel-intersections. This statistical orientational disorder can be modelled by considering two limiting orientations of the benzene molecules.