Computational study of substitution of Al by Fe3+ in the AlPO4-5 framework

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

“…The energy trends are well captured by the effective Hamiltonian, achieving a correlation factor of 0.969, with a slope of 1.012, which shows the strong correlation between the two methods. As expected from previous work describing heteroatom distributions, [25][26][27][28][29][30][31]49,50,83,89,[93][94][95] some scattering is observed, as subtle structural effects finely control the precise distribution, and it is also apparent from Fig. 2 that they are not fully reproduced by the effective Hamiltonian in a number of configurations.…”

Interplay of water, extra-framework cations and framework atoms in the structure of low-silicazeolites: the case of the natural zeolite Goosecreekite as studied by computer simulation

“…On application to both heulandite and clinoptilolite, 27,32,33 excellent agreement is found with experimental distributions of Si and Al in the framework: similarly good agreement is also found for other zeolitic materials. [34][35][36][37][38] To date, however, these studies have been conducted on anhydrous zeolite models, which is evident in the contraction of the zeolite cavities and the shifting of E-FC towards the framework walls (from those found in the hydrated state) in the structures obtained in these studies. 27,32 Such displacements and contractions are, of course, expected and are observed during the dehydration of many zeolites, [39][40][41] particularly those with small pores and low-medium Si/Al.…”

Importance of Blocking Inaccessible Voids on Modeling Zeolite Adsorption: Revisited

“…Zeolite structures were relaxed using interatomic potential approaches. , This is commonly done when a large set of zeolite structures are studied for the good balance between accuracy and computational cost. The results of such type of calculations are in excellent agreement with experimental data, in terms of both geometry and thermodynamic properties. − In our study, we used the well-known shell-model potentials developed by Sanders et al to optimize the zeolite structures using lattice energy minimization techniques, as implemented in the GULP code. , Short range interactions were handled in real space within a cutoff of 16 Å, while Coulombic interactions were computed with the Ewald summation method . We used the Newton–Rapson minimizer for the structural relaxation, switching to the RFO method once a large degree of relaxation was achieved, to ensure that real minima were reached (all vibrational frequencies are real numbers) .…”