Pressure vs Temperature¶

Surfinpy has the functionality to generate phase diagrams as a function of pressure vs temperature based upon the methodology used in Molinari et al according to

$\gamma_{adsorbed, T, P} = \gamma_{bare} + ( C ( E_{ads, T} - RTln(\frac{p}{p^o})$

where $\gamma_{adsorbed, T, p}$ is the surface energy of the surface with adsorbed species at temperature (T) and pressure (P), $\gamma_{bare}$ is the suface energy of the bare surface, C is the coverage of adsorbed species, $E_{ads}$ is the adsorption energy,

$E_{ads, T} = E_{slab, adsorbant} - (E_{slab, bare} + n_{H_2O} E_{H_2O, T}) / n_{H_2O}$

where $E_{slab, adsorbant}$ is the energy of the surface and the adsorbed species, $n_{H_2O}$ is he number of adsorbed species,

$E_{H_2O, (T)} = E_{H_2O, (g)} - TS_{(T)}$

where $S_{(T)}$ is the experimental entropy of gaseous water in the standard state.

Usage¶

from surfinpy import utils as ut
from surfinpy import p_vs_t

adsorbant = -14.00
SE = 1.40

stoich = {'Cation': 24, 'X': 48, 'Y': 0, 'Area': 60.22,
          'Energy': -575.00, 'Label': 'Bare'}
H2O =    {'Cation': 24, 'X': 48, 'Y': 2, 'Area': 60.22,
          'Energy': -605.00, 'Label': '1 Water'}
H2O_2 =  {'Cation': 24, 'X': 48, 'Y': 8, 'Area': 60.22,
          'Energy': -695.00, 'Label': '2 Water'}
data = [H2O, H2O_2]

coverage = ut.calculate_coverage(data)

thermochem = ut.read_nist("H2O.txt")

system = p_vs_t.calculate(stoich, data, SE,
                          adsorbant,
                          thermochem,
                          coverage)
system.plot()

Alternatively you can also tweak the style

system.plot(output="dark_pvt.png",
            set_style="dark_background",
            colourmap="PiYG")