First principles reactive simulation for equation of state prediction.

Area of Science:

• Computational Chemistry
• Materials Science
• High Explosives

Background:

• Density functional theory (DFT) is computationally expensive, limiting ab initio equation of state (EOS) predictions.
• Accurate EOS prediction is crucial for assessing high explosive performance.

Purpose of the Study:

• To perform an ab initio performance analysis of the high explosive pentaerythritol tetranitrate (PETN).
• To identify and quantify the limitations of DFT in predicting the EOS of PETN.

Main Methods:

• Utilized large-scale computing, advanced simulation techniques, and data science strategies.
• Compared DFT predictions with experimental data and thermochemical predictions.
• Employed high-level electronic structure calculations to analyze energetic bias.

Main Results:

• DFT systematically overestimates the energy of PETN detonation products relative to the unreacted material.
• This leads to underprediction of detonation velocity, pressure, and temperature at the Chapman-Jouguet state.
• An energetic bias in DFT predictions was identified and partially explained by electronic structure calculations.

Conclusions:

• DFT exhibits quantitative limitations for EOS prediction and high explosive assessment.
• A modeling strategy was developed for chemical composition mapping across parameter spaces.
• Additional molecular species were suggested for consideration in thermochemical modeling.