aC_JCP_2023_test

Test split from the 216-atom amorphous portion of the aC_JCP_2023 dataset. The amorphous carbon dataset was generated using ab initio calculations with VASP software. We utilized the LDA exchange-correlation functional and the PAW potential for carbon. Melt-quench simulations were performed to create amorphous and liquid-state structures. A simple cubic lattice of 216 carbon atoms was chosen as the initial state. Simulations were conducted at densities of 1.5, 1.7, 2.0, 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, and 3.5 g/cm3 to produce a variety of structures. The NVT ensemble was employed for all melt-quench simulations, and the density was adjusted by modifying the size of the simulation cell. A time step of 1 fs was used for the simulations. For all densities, only the Γ points were sampled in the k-space. To increase structural diversity, six independent simulations were performed.In the melt-quench simulations, the temperature was raised from 300 K to 9000 K over 2 ps to melt carbon. Equilibrium molecular dynamics (MD) was conducted at 9000 K for 3 ps to create a liquid state, followed by a decrease in temperature to 5000 K over 2 ps, with the system equilibrating at that temperature for 2 ps. Finally, the temperature was lowered from 5000 K to 300 K over 2 ps to generate an amorphous structure.During the melt-quench simulation, 30 snapshots were taken from the equilibrium MD trajectory at 9000 K, 100 from the cooling process between 9000 and 5000 K, 25 from the equilibrium MD trajectory at 5000 K, and 100 from the cooling process between 5000 and 300 K. This yielded a total of 16,830 data points.Data for diamond structures containing 216 atoms at densities of 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, and 3.5 g/cm3 were also prepared. Further data on the diamond structure were obtained from 80 snapshots taken from the 2 ps equilibrium MD trajectory at 300 K, resulting in 560 data points.To validate predictions for larger structures, we generated data for 512-atom systems using the same procedure as for the 216-atom systems. A single simulation was conducted for each density. The number of data points was 2,805 for amorphous and liquid states

本数据集为aC_JCP_2023数据集216原子无定形部分的测试子集。该无定形碳数据集基于VASP软件的从头算（ab initio）计算生成，我们采用了LDA交换关联泛函（LDA exchange-correlation functional）与碳的PAW势（PAW potential）。
为构建无定形与液态碳结构，我们开展了熔淬模拟。初始构型选用包含216个碳原子的简单立方晶格。
模拟在1.5、1.7、2.0、2.2、2.4、2.6、2.8、3.0、3.2、3.4及3.5 g/cm³的密度下开展，以获取多样化的结构。所有熔淬模拟均采用NVT系综（NVT ensemble），通过调整模拟盒尺寸调控体系密度。模拟时间步长设为1飞秒（fs）。针对所有密度，k空间仅采样Γ点（Γ points）。为提升结构多样性，我们共进行了六组独立模拟。
在熔淬模拟流程中，体系温度先在2皮秒（ps）内由300 K升至9000 K以完成碳的熔融；随后在9000 K下开展3皮秒的平衡分子动力学（MD, Molecular Dynamics）模拟以形成液态结构；接着在2皮秒内将温度降至5000 K，并在该温度下平衡2皮秒；最终在2皮秒内将温度从5000 K降至300 K，从而得到无定形结构。
熔淬模拟过程中，我们从9000 K下的平衡MD轨迹中抽取30个结构快照，从9000 K至5000 K的降温阶段抽取100个快照，从5000 K下的平衡MD轨迹中抽取25个快照，从5000 K至300 K的降温阶段抽取100个快照。最终总计得到16830个数据点。
我们还制备了密度分别为2.4、2.6、2.8、3.0、3.2、3.4及3.5 g/cm³的216原子金刚石结构数据集。此外，通过从300 K下的2皮秒平衡MD轨迹中抽取80个快照，进一步获得了560个金刚石结构数据点。
为验证对更大尺度结构的预测能力，我们参照216原子体系的构建流程，生成了512原子体系的数据集。针对每个密度均开展了单次模拟，其中无定形与液态结构的数据点共计2805个。