Experimental IR study and ab initio modelling of ethylene adsorption in a MFI-type host zeolite

Abstract

Different ab initio methods and experimental results are used to investigate the effect of the adsorption of one ethylene molecule on silicalite-1, a MFI-type zeolite. We used simplified models to simulate a portion of a straight or sinusoidal channel of silicalite-1 at a quantum level. The calculated absorption spectra of the models are qualitatively in good agreement with the experimental FTIR spectrum of silicalite-1. Additionally we simulate the FTIR spectrum of the isolated ethylene molecule and that of an ethylene molecule in interaction with the above-mentioned zeolite models. Results are discussed depending on the method and specific basis set and compared with experiments and previous molecular dynamics simulations.

Keywords:

• ab initio
• FTIR spectroscopy
• modelling
• vibrational analysis

Acknowledgements

We acknowledge C. Adamo and L. Joubert for useful discussion and for the computer equipment support of the Ecole Nationale Supérieure de Chimie de Paris (ENSCP, UMR 7575–Laboratoire d'Electrochimie, chimie des interfaces et modélisation pour l'énergie). We also thank L. Manceron for constructive discussions (LADIR, Paris). Support from the Région Bourgogne for the computer equipment of the Institut Carnot de Bourgogne is gratefully acknowledged. We also wish to thank the GDR 3152 ‘SpecMo’ and the GDR 2997 ‘COMOVI’ of the CNRS.