The thermal decomposition of CL-20 (C6H6N12O12)

This tutorial is proposed to develop a Deep Potential for the thermal decomposition of CL-20, perform MD simulations, and then use the ReacNetGenerator to analyze reactions.

This tutorial introduces the following research article: Liqun Cao, Jinzhe Zeng, Bo Wang, Tong Zhu, John Z.H. Zhang, Ab Initio Neural Network MD Simulation of Thermal Decomposition of High Energy Material CL-20/TNT, Physical Chemistry Chemical Physics, 2022, 24, 11801–11811. DOI: 10.1039/D2CP00710J

Reference dataset

In this study, a workflow was developed for making reference datasets with DP-GEN program. The details of each module in the workflow are given in this paper. You can install DP-GEN program with the tutorial in DP-GEN. In this example, the input files for DP-GEN program are provided here.

QM calculation

CP2K package was used for DFT calculation, which can be obtained at CP2k. PBE-D3 method was employed in this example, because it is generally used for DFT calculation of energetic materials.

Training of the NN PES

The DeepPot-SE (Deep Potential-Smooth Edition) model was used to train the NN potential by the DeePMD-kit program. Details of this method can be found in the paper. You can install DeePMD-kit program with the tutorial in DeePMD-kit.

Reactive molecular dynamic simulation

After training, the well-behaved NN PESs can be used for running molecular dynamics simulation by DeePMD-kit program.

Analysis by ReacNetGenerator

The trajectory of a single frame can be integrated into the entire trajectory, and the format of trajectory here is dump. The reaction mechanism can be obtained by the following command:

reacnetgenerator -i cl20.lammpstrj -a H C N O --type lammpsdumpfile --nohmm

The results can be viewed at this page.