posted on 2021-07-08, 19:35authored byMaxime Ducamp, François-Xavier Coudert
We
report a systematic study of the thermal and mechanical properties
of 134 pure SiO2 zeolites through density functional theory-based
calculations by making use of the quasi-harmonic approximation (out
of a total of 242 known fully ordered zeolitic frameworks). The comparison
of our results with reported experimental data for several zeolites
revealed a very good accuracy and validated our simulation methodology.
We observe a wide range of thermal expansion coefficients (from −5
to −35 MK–1), highlighting the great influence
of the framework topology over this physical property, while demonstrating
that all pure-silica zeolites exhibit negative thermal expansion.
Our simulations also provide a path for the computation of the bulk
modulus for each structure, as well as its pressure and temperature
dependence. Results revealed a large gamut of bulk modulus values
(from 8 to 134 GPa), showing that most frameworks display pressure-induced
softeningbut not all! Finally, this study provides some hints
to the open question of experimental feasibility of zeolitic frameworks,
showing that the experimentally synthesized structures appear to have
a distinct distribution of thermal and mechanical properties.