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Rules of formation of H–C–N–O compounds at high pressure and the fates of planetary ices
L.J. Conway, C.J. Pickard, A. Hermann
https://doi.org/10.1073/pnas.2026360118
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Contents:

- HCNO-AIRSS.tar.gz
	All 280,000+ structures generated using AIRSS in the H+C+N+O quaternary at 500GPa. The files are .res
files containing the crystal structures, energies, volumes and metadata concerning the CASTEP input
parameters. This data can be analysed using AIRSS with the following command:

ca -m -1 H -2 C -3 N -3 O

to extract the stable structures and:

ca -r

to extract the rankings of each stochiometry in the set. The outputs of these two commands can be
seen in output_500gpa.dat and rankings_500gpa.dat.


- HCNO-Optimised.tar.gz
	The best structures from the above dataset were determined using "cam" and "ca -m -p -$x" to
estimate stable structures at 500+x GPa with x=-400..200. These structures were then optimised at
a series of pressures using higher cut-off values and denser k-point grids. Details of this are in
REM blocks of the .res files.
	 There are output_*.dat files for each pressure included.

- Figs.tar.gz
	Data used to produce figures in the PNAS paper if they cannot be reproduced using "ca":

	-Fig1B.dat
		x,y and enthalpy values on the "balanced redox" plane at 500GPa

	-Fig2A.dat
		Enthalpy-Pressure data for HCNO and decomposition reactions

	-Fig2C.dat
		HCNO Pca21 - II band structure.

	-Fig4B.tar.gz
		COHP data

	-Fig6A.dat
		x,y and enthalpy values on the "balanced redox" plane at 100GPa

	-FigS1-*.dat
		Enthalpy-Pressure data for stable structures and decomposition reactions

	-FigS5.tar.gz
		Band Structure data for CN2O6

	-FigS8-*.dat
		Enthalpy-Pressure data for metastable structures and decomposition reactions

	-FigS16.tar.gz
		Phonon Dispersion curves for stable structures.