SAFT

The Statistical Associating Fluid Theory (SAFT) equation of state (EOS) is based on first order perturbation of the residual Helmholtz energy. The total Helmholtz energy is then defined as the sum of ideal gas, monomer (i.e. segment or group), chain (i.e. component), and association terms.

\(\frac{A}{N k_{B} T}=\frac{A^{ideal}}{N k_{B} T}+\frac{A^{mono.}}{N k_{B} T}+\frac{A^{chain}}{N k_{B} T}+\frac{A^{assoc.}}{N k_{B} T}\)

The ideal and association terms are defined in the main saft object. The monomer and chain terms (or others such as \(A^{elec.}\) for electrolytes) are defined in a more specific object that the main saft class will import. This secondary class will provide the radial distribution function used by the association term with the method, gr_assoc.

despasito.equations_of_state.saft.saft.EosType([...])

Initialize EOS object for SAFT variant.

despasito.equations_of_state.saft.saft.saft_type(name)

Initialize EOS object for SAFT variant.

SAFT-𝛾-Mie

EOS type: saft.gamma_mie

This heteronuclear version of SAFT uses the Mie potential to not only offer a group contribution EOS but a means to connect thermodynamic properties to bead definitions that can be simulated.

Papaioannou, V. et. al, J. Chem. Phys. 140, 054107 (2014); https://doi.org/10.1063/1.4851455

despasito.equations_of_state.saft.gamma_mie.SaftType(...)

Object of SAFT-𝛾-Mie

Supporting Functions

despasito.equations_of_state.saft.compiled_modules.ext_gamma_mie_python

Routines for calculating the Helmholtz energy for the SAFT-gamma equation of state.

SAFT-𝛾-SW

EOS type: saft.gamma_sw

This heteronuclear version of SAFT uses the square-wave potential to not only offer a group contribution EOS but a means to connect thermodynamic properties to bead definitions that can be simulated.

Lymperiadis, A. et. al, J. Chem. Phys. 127, 234903 (2007); https://doi.org/10.1063/1.2813894

despasito.equations_of_state.saft.gamma_sw.SaftType(...)

Object of SAFT-𝛾-SW (for square well potential)

General Functions

despasito.equations_of_state.saft.saft_toolbox

General functions that are applicable to multiple SAFT variants

despasito.equations_of_state.saft.Aideal

EOS object for SAFT ideal gas contributions to the Helmholtz energy with Aideal_contribution()

despasito.equations_of_state.saft.Aassoc

EOS object for SAFT association sites contributions to the Helmholtz energy