Modeling the sorption dynamics of NaH using a reactive force field.

Area of Science:

• Computational materials science
• Chemical physics
• Nanotechnology

Background:

• Sodium hydride (NaH) is a key material in various chemical processes.
• Accurate simulation of NaH behavior requires reliable force fields.
• Ab initio methods provide high-fidelity data but are computationally expensive for large systems.

Purpose of the Study:

• To develop and validate a reactive force field, ReaxFF(NaH), for simulating sodium hydride.
• To investigate the dynamics of hydrogen desorption from NaH nanoparticles.
• To understand the influence of nanostructuring on NaH decomposition.

Main Methods:

• Parametrization of a reactive force field (ReaxFF) using ab initio data for NaH.
• Validation against ab initio heats of formation and equations of state.
• Molecular dynamics simulations of hydrogen desorption and thermal decomposition.

Main Results:

• ReaxFF(NaH) accurately reproduces ab initio heats of formation and equations of state for NaH.
• Simulations reveal ReaxFF(NaH) correctly models charge transfer during hydrogen desorption.
• Heat of desorption strongly depends on NaH particle size, indicating nanostructuring enhances desorption.

Conclusions:

• The parametrized ReaxFF(NaH) force field is a reliable tool for simulating NaH.
• Nanostructuring NaH significantly enhances the hydrogen desorption process.
• Molecular dynamics simulations provide insights into NaH thermal decomposition consistent with experimental observations.