WLC model thermodynamics (isotensional)

class WLC(number_of_links, link_length, hinge_mass, persistance_length)

The worm-like chain (WLC) model thermodynamics in the isotensional ensemble.

The number of links in the chain.

The length of each link in the chain in units of nm.

hinge_mass

The mass of each hinge in the chain in units of kg/mol.

persistance_length

The persistance length of the chain in units of nm.

legendre

The thermodynamic functions of the model in the isotensional ensemble approximated using a Legendre transformation.

end_to_end_length(force, temperature)

The expected end-to-end length as a function of the applied force and temperature.

Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The end-to-end length \(\xi\).

Return type:

numpy.ndarray

The expected end-to-end length per link as a function of the applied force and temperature.

Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The end-to-end length per link \(\xi/N_b=\ell_b\gamma\).

Return type:

numpy.ndarray

nondimensional_end_to_end_length(nondimensional_force)

The expected nondimensional end-to-end length as a function of the applied nondimensional force.

Parameters:

nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

Returns:

The nondimensional end-to-end length \(N_b\gamma=\xi/\ell_b\).

Return type:

numpy.ndarray

The expected nondimensional end-to-end length per link as a function of the applied nondimensional force.

Parameters:

nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

Returns:

The nondimensional end-to-end length per link \(\gamma\equiv \xi/N_b\ell_b\).

Return type:

numpy.ndarray

gibbs_free_energy(force, temperature)

The Gibbs free energy as a function of the applied force and temperature,

\[\psi(\xi, T) = -kT\ln Q(\xi, T).\]
Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The Gibbs free energy \(\psi\).

Return type:

numpy.ndarray

The Gibbs free energy per link as a function of the applied force and temperature.

Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The Gibbs free energy per link \(\psi/N_b\).

Return type:

numpy.ndarray

relative_gibbs_free_energy(force, temperature)

The relative Gibbs free energy as a function of the applied force and temperature,

\[\Delta\psi(\xi, T) = kT\ln\left[\frac{P_\mathrm{eq}(0)}{P_\mathrm{eq}(\xi)}\right].\]
Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The relative Gibbs free energy \(\Delta\psi\equiv\psi(\xi,T)-\psi(0,T)\).

Return type:

numpy.ndarray

The relative Gibbs free energy per link as a function of the applied force and temperature.

Parameters:
  • force (numpy.ndarray) – The force \(f\).

  • temperature (float) – The temperature \(T\).

Returns:

The relative Gibbs free energy per link \(\Delta\psi/N_b\).

Return type:

numpy.ndarray

nondimensional_gibbs_free_energy(nondimensional_force, temperature)

The nondimensional Gibbs free energy as a function of the applied nondimensional force and temperature.

Parameters:
  • nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

  • temperature (float) – The temperature \(T\).

Returns:

The nondimensional Gibbs free energy \(N_b\vartheta=\beta\psi\).

Return type:

numpy.ndarray

The nondimensional Gibbs free energy per link as a function of the applied nondimensional force and temperature.

Parameters:
  • nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

  • temperature (float) – The temperature \(T\).

Returns:

The nondimensional Gibbs free energy per link \(\vartheta\equiv\beta\psi/N_b\).

Return type:

numpy.ndarray

nondimensional_relative_gibbs_free_energy(nondimensional_force)

The nondimensional relative Gibbs free energy as a function of the applied nondimensional force,

\[\beta\Delta\psi(\gamma) = \ln\left[\frac{\mathscr{P}_\mathrm{eq}(0)}{\mathscr{P}_\mathrm{eq}(\gamma)}\right].\]
Parameters:

nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

Returns:

The nondimensional relative Gibbs free energy \(N_b\Delta\vartheta=\beta\Delta\psi\).

Return type:

numpy.ndarray

The nondimensional relative Gibbs free energy per link as a function of the applied nondimensional force,

\[\Delta\vartheta(\gamma) = \ln\left[\frac{\mathscr{P}_\mathrm{eq}(0)}{\mathscr{P}_\mathrm{eq}(\gamma)}\right]^{1/N_b}.\]
Parameters:

nondimensional_force (numpy.ndarray) – The nondimensional force \(\eta\equiv\beta f\ell_b\).

Returns:

The nondimensional relative Gibbs free energy per link \(\Delta\vartheta\equiv\beta\Delta\psi/N_b\).

Return type:

numpy.ndarray