Screening heteroatom distributions in zeotype materials using an effective Hamiltonian approach: the case of aluminogermanate PKU-9

Abstract

We introduce a method to allow the screening of large configurational spaces of heteroatom distributions in zeotype materials. Based on interatomic potential calculations of configurations containing up to two heteroatoms per cell, we parameterize an atomistic effective Hamiltonian to describe the energy of multiple substitutions, with consideration of both short- and long-range interactions. Then, the effective Hamiltonian is used to explore the full configurational space at other compositions, allowing the identification of the most stable structures for further analysis. We illustrate our approach with the aluminogermanate PKU-9, where we show that increasing the aluminium concentration changes the likely siting of Al, in agreement with experiment.

The Si–Ge substitutional series in the chiral STW zeolite structure type

“…To deal with this, we employ a recently developed method that evaluates the energy of the system using an effective Hamiltonian (EH, see Supplementary Information). [32,33] The EH was parameterized using the lattice energy of the pure SiO 2 STW zeolite and the substitution energies for 1 to 4 Ge atoms by unit cell computed with interatomic potentials. Explicit calculations of the lattice energy are computed for the whole set of possible symmetry nonredundant configurations up to 3 Ge by unit cells.…”

“…For larger increase of the minority element in the binary solid solution, the number of configurations increases exponentially and therefore it is not possible to compute their energy. To deal with this, we turn to the recently developed Effective Hamilton ian (EH) approach [32], which parametrise the atom-atom interaction in a simple numerical function. In this way, the energy of millions of configurations can be evaluated at a small computational cost.…”