Surface tension diagram of a pure substance

from feos.si import *
from feos.dft import HelmholtzEnergyFunctional, PhaseDiagram, SurfaceTensionDiagram
from feos.pcsaft import PcSaftParameters
import matplotlib.pyplot as plt
import seaborn as sns
import pandas as pd

sns.set_context('talk')
sns.set_palette('Dark2')
sns.set_style('ticks')
colors = sns.palettes.color_palette('Dark2', 1)

parameters = PcSaftParameters.from_json(
    substances=['methanol'],
    pure_path='../parameters/pcsaft/gross2002.json'
)
functional = HelmholtzEnergyFunctional.pcsaft(parameters)

phase_diagram = PhaseDiagram.pure(functional, 150 * KELVIN, 25)

st_diagram = SurfaceTensionDiagram(
    phase_diagram.states,
    n_grid=1024
)

sns.lineplot(
    y=st_diagram.surface_tension / (MILLI * NEWTON / METER),
    x=st_diagram.liquid.temperature / KELVIN
)
sns.scatterplot(
    y=st_diagram.surface_tension / (MILLI * NEWTON / METER),
    x=st_diagram.liquid.temperature / KELVIN,
    clip_on=False
)
sns.despine(offset=10)
plt.xlim(100, 600)
plt.ylim(0, 50)
plt.xlabel(r'$T$ / K')
plt.ylabel(r'$\gamma$ / mN m$^{-1}$');