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Origin of short- and medium-range order in supercooled liquid Ge 3 Sb 2 Te 6 from ab initio molecular dynamics simulations
Phase-change materials such as Ge–Sb–Te compounds have attracted much attention due to their potential value in electrical data storage. In contrast to the amorphous and crystalline phases, supercooled liquids are far from being deeply understood despite their inevitable role in both amorphization and crystallization processes. To this end, we have studied the dynamics properties and structural characteristics of liquid and supercooled liquid Ge 3 Sb 2 Te 6 during the fast cooling process. As the temperature decreases, chemical bonds become more homogeneous, but coordination numbers of Ge, Sb and Te atoms change very little. Meanwhile, the structural order of short-range configuration is obviously enhanced. Further studies suggest that Ge-centered, Sb-centered and Te-centered configurations change to the more ordered defective octahedrons mainly by adjusting the bond-angle relationship and bond length, rather than just by changing the coordination environment. It is the more ordered octahedrons that promote the formation of medium-range order. Our findings provide a deep insight into the origin of local structural order in supercooled liquid Ge 3 Sb 2 Te 6 , which is of great importance for the comprehensive understanding of amorphization and crystallization processes.
Free and internal energies for the adsorption of short alkanes into the zeolite SSZ-13 from ab initio molecular dynamics simulations
We useab initiomolecular dynamics simulations to calculate the temperature dependent free energy and internal energy of adsorption of short alkanes into the zeolite SSZ-13.
Exploring non-adiabaticity to CO reduction reaction through ab initio molecular dynamics simulation
Non-adiabatic chemical reaction refers to the electronic excitation during reactions. This effect cannot be modeled by the ground-state Born-Oppenheimer molecular dynamics (BO-MD), where the electronic structure is at the ground state for every step of ions' movement. Although the non-adiabatic effect has been explored extensively in gas phase reactions, its role in electrochemical reactions, such as water splitting and CO 2 reduction, in electrolyte has been rarely explored. On the other hand, electrochemical reactions usually involve electron transport; thus, a non-adiabatic process can naturally play a significant role. In this work, using one-step CO 2 reduction as an example, we investigated the role of the non-adiabatic effect in the reaction. The reaction barriers were computed by adiabatic BO-MD and non-adiabatic real-time time dependent density functional theory (rt-TDDFT). We found that by including the non-adiabatic effect, rt-TDDFT could increase the reaction barrier up to 6% compared to the BO-MD calculated barrier when the solvent model is used to represent water. Simulations were carried out using explicit water molecules around the reaction site under different overpotentials, and similar non-adiabatic effects were found.
Ab initio Molecular Dynamics Simulations of Rare Earth (III) Ion Desorption from Silica Surfaces.
Abstract not provided.
Ab initio Molecular Dynamics of Isotope Separation in Porous Organic Cages.
Abstract not provided.
Enhanced Cu(2+) Dimerization on Mineral Surfaces ? an ab initio Molecular Dynamics Free Energy Study.
Abstract not provided.
Studying Molecular Reactions and Interactions at the Surface of Sea Spray Aerosols using Ab Initio Molecular Dynamics.
Abstract not provided.
Entrapment of Volatile Organic Compounds in Defective UiO-66 Metal-Organic-Framework: Ab Initio Molecular Dynamics Simulations at 300K
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Entrapment of VOCs in Defective UiO-66 MOF: Ab Initio Molecular Dynamics Simulations at 300K
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