PREDICTION OF TEMPLATE LOCATION VIA A COMBINED MONTE CARLO-SIMULATED ANNEALING APPROACH

A combined Monte Carlo-simulated annealing approach has been developed to predict the location and orientation adopted by organic molecules within a zeolite host. Periodic boundary conditions were used througho ut the simulations in order to permit a full treatment of organic-orga nic interactions within a densely packed system. This approach has bee n used to investigate the relationship between zeolite products and th e organic template molecules used in their synthesis. The results are shown to reproduce experimentally determined locations accurately, inc luding important disordering effects. Previous experimental work has s hown that some template molecules can effect the synthesis of more tha n one type of zeolite framework when experimental conditions are varie d and also that many zeolites can be synthesised by an apparently dive rse range of templates. Our results show that both these observations can still be rationalised via the 'templating theory' of zeolite synth esis. A mechanism for faulting is proposed which is shown to be consis tent for NU-86 and the industrially important zeolite beta.