An algorithm for very high pressure molecular dynamics simulations

Area of Science:

• Computational chemistry
• Molecular dynamics simulations
• High-pressure physics

Background:

• Simulating molecular behavior under extreme pressures is challenging.
• Accurate modeling requires considering environmental interactions.

Purpose of the Study:

• To introduce and validate the XP-GAS (eXtreme Pressure by Gas Atoms in a Sphere) simulation method.
• To assess the impact of environmental representation on high-pressure simulations.

Main Methods:

• Development of the XP-GAS algorithm using a fictitious ideal gas.
• Application to molecular clusters with quantum chemistry, Molecular Mechanics, or QM/MM.
• Comparison with the XP-PCM (QM/Continuum) model.
• Case study: conformational dynamics of 1,3-butadiene up to 15 GPa.

Main Results:

• XP-GAS QM/MM simulations show good agreement with XP-PCM (Cammi model) for static properties.
• Simulations highlight the importance of realistic medium representation in XP-GAS.
• Conformational dynamics of butadiene were effectively studied under high pressure.

Conclusions:

• XP-GAS is a viable method for simulating molecular systems under extreme pressures.
• Realistic medium modeling is crucial for accurate pressure effect predictions.
• The study validates XP-GAS for ground and excited state dynamics.