Polarizable force field development and molecular dynamics study of phosphate-based glasses

Area of Science:

• Materials Science
• Computational Chemistry
• Solid State Chemistry

Background:

• Phosphate-based glasses are crucial for biomedical applications.
• Understanding their atomic structure is key to tailoring their properties.
• Previous studies lacked detailed atomic-level insights into specific compositions.

Purpose of the Study:

• To perform molecular dynamics simulations of phosphate-based glasses.
• To characterize the atomic structure of P(2)O(5)-CaO-Na(2)O glasses.
• To investigate the influence of composition on glass structure.

Main Methods:

• Utilized molecular dynamics simulations with a parameterized interatomic force field.
• Incorporated polarization effects using the shell-model potential.
• Modified DL_POLY code (version 2.20) for high-temperature shell dynamics.
• Analyzed three specific molar compositions: (P(2)O(5))(0.45)(CaO)(x)(Na(2)O)(0.55-x) for x = 0.30, 0.35, and 0.40.

Main Results:

• Achieved good agreement with experimental and ab initio data.
• Demonstrated that phosphorus atoms bond to two or three bridging oxygens, depending on composition.
• Revealed that Na(+) and Ca(2+) ions occupy pseudo-octahedral environments.
• Reported mean oxygen coordination numbers of 6.55 for Na(+) and 6.85 for Ca(2+) across compositions.

Conclusions:

• The study successfully characterized the atomic structure of phosphate-based glasses using molecular dynamics.
• Simulation results provide a detailed understanding of bonding and coordination in these glasses.
• The findings are valuable for the design of phosphate-based glasses for biomedical applications.