Theoretical Study on a 42 T Model of Beta Zeolite by Density Functional Theory Simulation

Density functional theory was applied to study the structure of Beta zeolite. A model cluster containing 41Si atoms,1 Al atom,70 O atoms and 29 H atoms was constructed. The model structures were optimized using the Becke's three-parameter hybrid method with the Lee-Yang-Parr correlation functional (B3LYP) and the 6-31G basis set applying the Gaussian03 program package. The NMR parameters were calculated to validate the rationality of the model. It was found that in the optimization models,all O-H bond lengths were in range of 0.984～0.985 (A),among which the model with O-H bond length of 0.98478 (A) was more stable than the others. The ~1H and ~(27) Al chemical shifts of the most stable model were 4.03434 and 55.74 ppm,which were pretty consistent with Larry's experimental data of 4.1 and 54 ppm. The relationship between other structure parameters and total relative electric energy has also been found. All the results exhibit that the 42 T (the total number of Si and AI atoms is 42) model has common properties of the standard of zeolite Beta.