How to find a Decomposition of unstable compound into stable compounds (Pymatgen, materials project)

[sachin-rangaswamy]

Can anybody help with this!! I want know the module in Pymatgen where it can find the decomposition of unstable compound(random) into stable compounds like how the materials project does. I have attached the picture of reference where LiScVO₄
mp-754728 being unstable compound decomposes into stable compounds 5⁄42[V₂O₃]+ 8⁄21[Li₃VO₄] + 1⁄7[VO₂] + 5⁄14[Sc₂O₃] . Please if someone know the method or the module in Pymatergen to how to access this, it would be a great help, thank you! .

[janosh]

this data comes from PhaseDiagram.get_decomp_and_phase_separation_energy:

pymatgen/pymatgen/analysis/phase_diagram.py

Lines 831 to 855 in dca98be

	def get_decomp_and_phase_separation_energy(
	self,
	entry: PDEntry,
	space_limit: int = 200,
	stable_only: bool = False,
	tols: Sequence[float] = (1e-8,),
	maxiter: int = 1000,
	**kwargs: Any,
	) -> tuple[dict[PDEntry, float], float] | tuple[None, None]:
	"""
	Provides the combination of entries in the PhaseDiagram that gives the
	lowest formation enthalpy with the same composition as the given entry
	excluding entries with the same composition and the energy difference
	per atom between the given entry and the energy of the combination found.
	For unstable entries that are not polymorphs of stable entries (or completely
	novel entries) this is simply the energy above (or below) the convex hull.
	For entries with the same composition as one of the stable entries in the
	phase diagram setting `stable_only` to `False` (Default) allows for entries
	not previously on the convex hull to be considered in the combination.
	In this case the energy returned is what is referred to as the decomposition
	enthalpy in:

[sachin-rangaswamy]

Thank you very much!!

[sachin-rangaswamy]

In order to run this function I understand that I need two arguments and I am able to produce self argument. But how do I produce PDEntry for the entry argument ?

[janosh]

PDEntry just requires a composition and an energy. those can come from anywhere. in the case of MP it's usually the PBE or r2SCAN DFT energy