Elizaveta Sidler^1*, Raffaela Cabriolu^1*

1 Department of Physics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, Trondheim, 7491, Norway

* Corresponding authors emails: elizaveta.sidler@ntnu.no, raffaela.cabriolu@ntnu.no

DOI10.24435/materialscloud:mq-3k [version v1]

Publication date: Aug 20, 2024

How to cite this record

Elizaveta Sidler, Raffaela Cabriolu, Structural transitions of calcium carbonate by molecular dynamics simulation, Materials Cloud Archive 2024.125 (2024), https://doi.org/10.24435/materialscloud:mq-3k

Description

Calcium carbonate (CaCO₃) plays a crucial role in the global carbon cycle, and its phase diagram is of significant scientific interest. We used molecular dynamics to investigate selected structural phase transitions of calcium carbonate. Using the Raiteri potential, we explored the structural transitions occurring at the constant pressure of 1 bar, with temperatures ranging from 300 to 2500 K, and at the constant temperature of 1600 K, with pressures ranging from 0 to 13 GPa. With increasing temperature, the transitions between calcite, CaCO₃-IV, and CaCO₃-V were characterized. In the calcite structure, the carbonate ions are ordered in a planar triangular arrangement, alternating with layers of calcium ions. As the temperature increases, the transition from calcite to CaCO₃-IV occurs, leading to partial disordering of the carbonate ions. At higher temperatures, CaCO₃-IV transforms into CaCO₃-V. Through free energy analysis, we classified the latter transition as a continuous phase transition. At a temperature of 2000 K, a 'disordered CaCO₃' structure appears, characterized by low order within the calcium and carbonate sublattices and the free rotation of the carbonate ions. With increasing pressure, two calcium carbonate transformations were observed. At P = 2 GPa, the CaCO₃-V phase undergoes a phase transition into CaCO₃-IV, demonstrating that the model can describe the transition between these two phases as pressure- and temperature-driven. At P = 4.25 GPa, CaCO₃-IV undergoes a phase transition into the CaCO₃-Vb phase. This transition is classified as first-order based on free energy calculations.

Materials Cloud sections using this data

Files

File name	Size	Description
npt_T_300_Np_3360.data MD5md5:eaeba29dce1ad2b8fdae88a2b0c8d7c0	549.3 KiB	LAMMPS configuration file (system with 3360 particles equilibrated at a temperature of 300 K and a pressure of 1 bar)
npt_T_300_Np_9900.data MD5md5:942bfbce71eca05a7bb681f60ec05022	1.6 MiB	LAMMPS configuration file (system with 9900 particles equilibrated at a temperature of 300 K and a pressure of 1 bar)
npt_T_300_Np_14520.data MD5md5:6c4347da8c6350e1763c3af21fd766a6	2.4 MiB	LAMMPS configuration file (system with 14520 particles equilibrated at a temperature of 300 K and a pressure of 1 bar)
npt_T_1600_Np_15360.data MD5md5:496658f1064fe4c314fc881b0238615b	2.5 MiB	LAMMPS configuration file (system with 15360 particles equilibrated at a temperature of 1600 K and a pressure of 1 bar)
plumed_temp.dat MD5md5:0f32696e157eeb53c4f9b9684d9b8992	487 Bytes	PLUMED input file (metadynamics simulations for temperature-driven transitions)
plumed_press.dat MD5md5:6449c08e163c62cac23b10ba3d6b0254	497 Bytes	PLUMED input file (metadynamics simulations for pressure-driven transitions)
index.ndx MD5md5:813c0d9a4df4200b2d48cb7ec7bed1d5	47.3 KiB	'index' file required by PLUMED
in_temp.lammps MD5md5:0f457dc11b373715269051d2f3b7e4d6	3.1 KiB	LAMMPS input file (molecular dynamics simulations at different temperatures and a pressure of 1 bar)
in_press.lammps MD5md5:92359248aecfd7fe741bccec47299bd1	3.1 KiB	LAMMPS input file (molecular dynamics simulations at a temperature of 1600 K and different pressures)

License

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External references

Keywords

calcium carbonate phase transitions molecular dynamics metadynamics high pressure high temperature