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The ModTangToennies class, found in pykingas/multiparam.py, inherrits from the py_KineticGas class, and is the interface to the Modified Tang-Toennies Model. This class implements utility methods to access mixing parameters etc.

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Constructor

Methods to initialise Modified Tang-Toennies model.

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__init__(self, comps, quantum_active=True, parameter_ref='default')

Initialize modified Tang-Toennies potential

Args:

     comps (str) :

          Single component identifier

     parameter_ref (str, optional) :

          Identifier for parameter set to use

Utility methods

Set- and get methods for interaction parameters, mixing parameters …

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JKWB_phase_shift(self, i, j, l, E)

Compute the phase shift for a collision with angular momentum quantum number l and energy E, using the JKWB approximation Args: i, j (int): Species indices l (int): Angular momentum quantum number E (float): Total energy (J) Returns: float: The relative phase shift $(- \pi / 2, \pi / 2)$

JKWB_upper_E_limit(self, i=0, j=None)

Get the upper energy limit for when the JKWB approximation is automatically applied.

cross_section(self, i, j, l, E, reduced=False)

Calculate the collision cross section. If reduced=True, return the cross section divided by the hard-sphere cross section.

de_broglie_wavelength(self, i, T)

Get the de Broglie wavelength of species i at temperature T.

get_de_boer(self, i=None, j=None)

Get the de Boer parameter

get_quantum_active(self)

Get the current quantum_active state.

get_r_min(self, i, j)

Compute the position of the potential minimum.

Args:

     i, j (int):

          Species indices

Returns:

     float :

          r_min (m)

get_reducing_units(self, i=0, j=None)

See py_KineticGas.

omega(self, i, j, n, s, T)

Calculate the collision integral $\Omega^{(n, s)}$ as defined in The Limits of the Feynman-Hibbs corrections … paper (see cite page).

This method uses quantum mechanical or classical calculation based on whether self.get_quantum_active() is True

phase_shift(self, i, j, l, E)

Compute the phase shift for a collision with angular momentum quantum number l and energy E Args: i, j (int): Species indices l (int): Angular momentum quantum number E (float): Total energy (J) Returns: float: The relative phase shift $(- \pi / 2, \pi / 2)$

potential(self, r)

Evaluate potential

Args:

     r (float) :

          Distance (m)

Returns:

     float :

          Potential (J)

potential_dn(self, r, n)

Calculate the n‘th derivative of the potential wrt. distance. Args: r (float) : Distance (m)

Returns: float : Potential n’th derivative wrt. distance (J / m^n)

potential_r(self, r)

Evaluate potential derivative wrt. distance

Args:

     r (float) :

          Distance (m)

Returns:

     float :

          Potential derivative wrt. distance (N)

potential_rr(self, r)

Evaluate potential second derivative wrt. distance

Args:

     r (float) :

          Distance (m)

Returns:

     float :

          Potential second derivative wrt. distance (N / m)

quantum_omega(self, i, j, n, s, T)

Calculate the quantal collision integral $\Omega^{(n, s)}$ as defined in The Limits of the Feynman-Hibbs corrections … paper (see cite page).

set_de_boer_mass(self, i, de_boer)

Set the particle mass to get the specified de Boer parameter

set_quantum_active(self, active)

Activate/deactivate quantum mechanical calculation of things.

vdw_alpha(self)

Get the dimensionless Van der Waals alpha-parameter

Returns:

     float :

          alpha (-)

wave_function(self, i, j, l, E, r_end, dr=0.1)

Solve the Schrödinger equation for the two-particle wave function at energy E, out to the distance r_end

Args:

     i, j (int):

          Species indices

     l (int):

          Angular momentum quantum number

     E (float):

          Total energy (J)

     r_end (float):

          Maximum particle separation (m)

     dr (float):

          Step size

Returns:

     list[float] :

          The two-particle non-normalized wave function out to r_end.