Theoretical Investigation of the MQMAS NMR Characteristics from the ab initio Molecular Dynamics for CHA Zeolite

This is a poster we presented to MC14 in Birmingham.
It covers an overview on coupling of ab-initio MD simulation and NMR simulations.

Transcript

1. Non-Cognitive Predictors of Student Success: A Predictive Validity Comparison Between Domestic and International Students Simulation of realistic NMR spectra of zeolites Non-Cognitive Predictors of Student Success: A Predictive Validity Comparison Between Domestic and International Students INTRO: • NMR is crucial to investigate zeolite • 27Al-NMR difficult because of quadrupolar momentum o Need of simulations • Usually NMR simulation zeolite are coarse o Small unit cell, UHV, no water, no Temperature • Idea: ab-initio Molecular Dynamics (MD) + NMR theoretical spectra METHOD Our model: Na-Chabazite (Si/Al=11/1) minimal cell with 5 water molecules. 1. Geometry optimization with density functional level (DFT) 2. Ab-initio run of MD at 300K 3. Sampling of structures from the run 4. Calculations of the NMR response (GIPAW) RESULTS NMR response: Not clear trend present yet! • Need to consider other more complex paramenter (e.g. fractional number of waters, Na response) • (n. Water/u.f > 3) solvation-desolvation equilibrium PRESENTER: Federico Brivio Federico.brivio@natur.cuni.cz Theoretical Investigation of the MQMAS NMR Characteristics from the ab initio Molecular Dynamics for CHA Zeolite Song Lu, Chen Lei, Federico Brivio, Petr Nachtigall Department of Physical and Macromolecular Chemistry, Charles University, Hlavova 8, 128 43, Czechia. Geom-OPT and MD with VASP o 700 eV cut-off, Gamma point, PBE o MD NVT o Dispersion forces: DFT-D3 NMR spectra with CASTEP o Analogous parameter of VASP o Particular of the Na configuration in the DFT optimized structure. Film by Gael Bardon from the Noun Project