Coefficient of Thermal Expansion

CTEAnalyzer

CTEAnalyzer(
    temperatures: Sequence[float] = (300.0, 600.0, 900.0),
    ensemble: str = "npt_berendsen",
    pressure: float = 1.0,
    calculator: BaseCalculator | None = None,
    cte_transformation: CTETransformation | None = None,
)

A class used to estimate volumetric CTE from NPT-MD volume-temperature data.

Initializes the CTEAnalyzer object.

Parameters:

Name	Type	Description	Default
temperatures	Sequence[float]	Temperatures in Kelvin to sample with MD. Defaults to (300.0, 600.0, 900.0).	(300.0, 600.0, 900.0)
ensemble	str	MD ensemble applied to the calculator for every temperature in the sweep; must be one of the ensembles supported by BaseMDCalculator. Defaults to "npt_berendsen".	'npt_berendsen'
pressure	float	Target pressure in atm, applied to the calculator for every temperature in the sweep. Defaults to 1.0.	1.0
calculator	BaseCalculator | None	MD-capable calculator.	None
cte_transformation	CTETransformation | None	Transformation object used to generate the per-temperature structure copies. Defaults to a CTETransformation built from temperatures.	None

calculate

calculate(
    structure: Structure | Atoms, steps: int = 10000
) -> dict[str, list | float]

Calculates temperature-dependent volumes and volumetric CTE.

Parameters:

Name	Type	Description	Default
structure	Structure | Atoms	Input structure.	required
steps	int	Number of MD steps per temperature. Defaults to 10000.	10000

Raises:

Type	Description
ValueError	If steps is non-positive, fewer than two distinct temperatures are configured, or the calculator is not a BaseMDCalculator.

Returns:

Type	Description
dict[str, list | float]	dict[str, list | float]: Dictionary with keys: - temperatures: Configured temperatures in Kelvin. - volumes: Final volume for each temperature in A^3. - cte: Volumetric CTE in K^-1. - cte_ppm: Volumetric CTE in ppm/K.

cte_transformation

cte_transformation() -> CTETransformation

Return CTE transformation object used by this analyzer.

Returns:

Type	Description
CTETransformation	CTE transformation instance.