The role of the electrostatic potential, electric field and electric field gradient on the acidity of AFI and CHA zeotypes.
PHYS CHEM CHEM PHYS
177 - 185.
We consider the role of short- and long-range interactions in determining the acidity of microporous solids. Within the context of an interatomic forcefield approach and a correct treatment of long-range electrostatics we demonstrate the role of the electrostatic potential, electric field and electric field gradient in determining the vibrational frequency of a Bronsted acid centre. We demonstrate the applicability of these concepts for AlPO4-5, AlPO4-34, SSZ-24 and SSZ-13, in whose unit cells a single Bronsted acid site was introduced in the four different oxygens. Furthermore, we show, by using the energy required to elongate the OH bond-essentially the first stage of proton transfer-as a measure of acidity, how the vibrational frequency is related to the acid strength.
|Title:||The role of the electrostatic potential, electric field and electric field gradient on the acidity of AFI and CHA zeotypes|
|Keywords:||ELECTRONEGATIVITY EQUALIZATION METHOD, AB-INITIO CALCULATIONS, QUANTUM-CHEMISTRY CALCULATIONS, ZEOLITE-CATALYZED-REACTIONS, MECHANICS FORCE-FIELD, MOLECULAR-DYNAMICS, TOLUENE ALKYLATION, FIRST-PRINCIPLES, ATOMIC CHARGES, SILICA|
|UCL classification:||UCL > School of BEAMS > Faculty of Maths and Physical Sciences > Chemistry|
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