An ab initio study of adsorption related properties of diatomic molecules in zeolites

✍ Scribed by Frederik Tielens; Paul Geerlings

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 267 KB
• Volume: 166
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(00)00456-8

✦ Synopsis

A perturbational approach (M-method) for the calculation of the interaction energies of N 2 , O 2 , Ar and CO in zeolite cavities is presented. The calculation method is compared with the 'molecule in point charge environment' calculation and a full ab initio calculation tested along an axis connecting the center of the cavity with a site II cation. The Henry constants, heats of adsorption and separation constants for N 2 , O 2 and Ar in a NaY zeolite are obtained using the 'molecule in point charge environment' method and the present approximation. Different grid sizes were considered depending on the distance between adsorbing system and cation. A promising result, in particular for the separation constants, was found using the Van der Waals and ionic radii for the grid delimitation and the M-method calculated on the B3LYP/6-31G * level. CO was added as a final test system with lower symmetry.