Available thickness models

Functions calculating the thickness of an adsorbed layer as a function of pressure.

pygaps.characterisation.models_thickness.thickness_halsey(pressure: float) → float

Halsey thickness curve.

Applicable for nitrogen at 77K on materials with weakly interacting surfaces.

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

pygaps.characterisation.models_thickness.thickness_harkins_jura(pressure: float) → float

Harkins and Jura thickness curve.

Applicable for nitrogen at 77K on materials with weakly interacting surfaces.

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

pygaps.characterisation.models_thickness.thickness_zero(pressure: float) → float

A zero-thickness curve applicable for non-wetting adsorbates.

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

pygaps.characterisation.models_thickness.convert_to_thickness(loading, monolayer)

Conversion to a thickness is done by obtaining the number of adsorbed layers through dividing amount adsorbed by the amount adsorbed in a monolayer (as obtained by BET), then multiplying by the average thickness of a single layer. Mathematically:

\[t [nm] =\]

rac{n}{n_m} * 0.354

pygaps.characterisation.models_thickness.load_std_isotherm(name: str) → Callable

Load a standard isotherm, convert the loading to thickness, then fit an interpolator and then store it in memory.

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

Notes

pygaps.characterisation.models_thickness.SiO2_JKO(pressure: float) → float

Applicable for nitrogen at 77K on silica surfaces down to low pressures. [1]

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

References

[1]

Jaroniec, Mietek, Michal Kruk, and James P. Olivier. “Standard Nitrogen Adsorption Data for Characterization of Nanoporous Silicas.” Langmuir 15, no. 16 (August 1, 1999): 5410–13. https://doi.org/10.1021/la990136e.

pygaps.characterisation.models_thickness.CB_KJG(pressure: float) → float

Applicable for nitrogen at 77K on non-graphitized carbon materials down to low pressures. [2]

Parameters:

pressure (float) -- Relative pressure.

Returns:

float -- Thickness of layer in nm.

References

[2]

Kruk, Michal, Mietek Jaroniec, and Kishor P. Gadkaree. “Nitrogen Adsorption Studies of Novel Synthetic Active Carbons.” Journal of Colloid and Interface Science 192, no. 1 (August 1997): 250–56. https://doi.org/10.1006/jcis.1997.5009. .

pygaps.characterisation.models_thickness.get_thickness_model(model: str | Callable) → Callable

Return a function calculating an adsorbate thickness.

The model parameter is a string which names the thickness equation which should be used. Alternatively, a user can implement their own thickness model, either as an experimental isotherm or a function which describes the adsorbed layer. In that case, instead of a string, pass the Isotherm object or the callable function as the model parameter.

Parameters:

model (str or callable) -- Name of the thickness model to use.

Returns:

callable -- A callable that takes a pressure in and returns a thickness at that point.

Raises:

ParameterError -- When string is not in the dictionary of models.