示例#1
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 def test_get_pourbaix_entries(self):
     pbx_entries = self.rester.get_pourbaix_entries(["Fe"])
     for pbx_entry in pbx_entries:
         self.assertTrue(isinstance(pbx_entry, PourbaixEntry))
     # Ensure entries are pourbaix compatible
     pbx = PourbaixDiagram(pbx_entries)
     # Try binary system
     pbx_entries = self.rester.get_pourbaix_entries(["Fe", "Cr"])
     pbx = PourbaixDiagram(pbx_entries)
示例#2
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def stable_mat_one_elem(pH, V, mat):
    """
	Returns pymatgen pourbaix entry object corresponding to most stable species

	Args:
		pH: pH of system
		V: Potential with reference to the Standard Hydrogen Electrode (SHE)
	"""
    # | -  - stable_mat_one_elem
    from pourdiag_single import pourdiag_single as pd_sgle
    from pymatgen.analysis.pourbaix.maker import PourbaixDiagram
    # Access entry Gibbs(pH, V)
    from pymatgen.analysis.pourbaix.analyzer import PourbaixAnalyzer

    pH = 0
    V = 1
    mat = 'Pt'

    all_entries = pd_sgle(mat)

    pourbaix = PourbaixDiagram(all_entries)
    PA = PourbaixAnalyzer(pourbaix)

    templist = []
    for i in all_entries:
        templist.append(PA.g(i, pH, V))
    minE = min(templist)

    for i in all_entries:
        if PA.g(i, pH, V) == minE:
            StableSpec = i
    return StableSpec  # Returns the entries object of the stable species
示例#3
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def is_solid_phase(mat1, mat2, mat1_co=0.5):
    """Returns TRUE is there exists a all solid phase in the binary Pourbaix
    Diagram this means that the phase doesn't have any aqueous species.
    """
    mat2_co = 1 - mat1_co

    pd_b = pd_entries(mat1, mat2)

    pd = PourbaixDiagram(pd_b, {mat1: mat1_co, mat2: mat2_co})
    pl = PourbaixPlotter(pd)
    ppd = pl.pourbaix_plot_data([[-2, 16], [-3, 3]])

    pd_lst = []
    cnt = 0
    for stable_entry in ppd[0]:
        pd_lst.append([])
        pd_lst[cnt].append(ppd[0][stable_entry])
        pd_lst[cnt].append(stable_entry.entrylist)
        cnt = cnt + 1

    solidphase = False
    for i in pd_lst:
        if len(i[1]) == 1:
            if i[1][0].phase_type == 'Solid':
                solidphase = True
        if len(i[1]) == 2:
            if i[1][0].phase_type and i[1][1].phase_type == 'Solid':
                solidphase = True

    return solidphase
示例#4
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 def setUp(self):
     module_dir = os.path.dirname(os.path.abspath(__file__))
     (elements, entries) = PourbaixEntryIO.from_csv(
         os.path.join(module_dir, "test_entries.csv"))
     self.num_simplices = {
         "Zn(s)": 7,
         "ZnO2(s)": 7,
         "Zn[2+]": 4,
         "ZnO2[2-]": 4,
         "ZnHO2[-]": 4
     }
     self.e_above_hull_test = {"ZnHO[+]": 0.0693, "ZnO(aq)": 0.0624}
     self.decomp_test = {
         "ZnHO[+]": {
             "ZnO(s)": 0.5,
             "Zn[2+]": 0.5
         },
         "ZnO(aq)": {
             "ZnO(s)": 1.0
         }
     }
     self.pd = PourbaixDiagram(entries)
     self.analyzer = PourbaixAnalyzer(self.pd)
     self.multi_data = loadfn(os.path.join(test_dir, 'multicomp_pbx.json'))
     warnings.simplefilter("ignore")
示例#5
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 def test_v_fe(self):
     v_fe_entries = self.multi_data['v_fe']
     pd = PourbaixDiagram(v_fe_entries, comp_dict={"Fe": 0.5, "V": 0.5})
     analyzer_vfe = PourbaixAnalyzer(pd)
     entries = sorted(pd._all_entries, key=lambda x: x.energy)
     self.assertAlmostEqual(entries[1].weights[1], 0.6666666666)
     self.assertAlmostEqual(entries[1].energy, -110.77582628499995)
     self.assertAlmostEqual(entries[100].energy, -20.685496454465955)
示例#6
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 def setUp(self):
     module_dir = os.path.dirname(os.path.abspath(__file__))
     (elements, entries) = PourbaixEntryIO.from_csv(
         os.path.join(module_dir, "test_entries.csv"))
     self._entries = entries
     self._pd = PourbaixDiagram(entries)
     self.list_of_stable_entries = [
         "ZnO(s)", "Zn[2+]", "ZnO2(s)", "ZnHO2[-]", "ZnO2[2-]", "Zn(s)"
     ]
示例#7
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    def test_get_entry_stability(self):
        stab = self.analyzer.get_entry_stability(self.pd.all_entries[0], pH=0, V=1)
        self.assertAlmostEqual(stab, 3.88159999)

        # binary
        pd_binary = PourbaixDiagram(self.multi_data['binary'],
                                    comp_dict = {"Ag": 0.5, "Te": 0.5})
        analyzer_binary = PourbaixAnalyzer(pd_binary)
        ghull = analyzer_binary.get_entry_stability(self.multi_data['binary'][16], 
                                                    0, -5)
示例#8
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    def test_binary(self):
        # Test get_all_decomp_and_e_above_hull
        pd_binary = PourbaixDiagram(self.multi_data['binary'], 
                                    comp_dict = {"Ag": 0.5, "Te": 0.5})
        analyzer_binary = PourbaixAnalyzer(pd_binary)

        te_entry = pd_binary._unprocessed_entries[4]
        de, hull_e, entries = analyzer_binary.get_all_decomp_and_e_above_hull(te_entry)
        self.assertEqual(len(de), 10)
        self.assertEqual(len(hull_e), 10)
        self.assertAlmostEqual(hull_e[0], 5.4419792326439893)
示例#9
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 def test_ternary(self):
     # Ternary
     te_entry = self.multi_data['ternary'][20]
     pd_ternary = PourbaixDiagram(self.multi_data['ternary'],
                                  comp_dict = {"Ag": 0.33333, 
                                               "Te": 0.33333,
                                               "N": 0.33333})
     analyzer_ternary = PourbaixAnalyzer(pd_ternary)
     de, hull_e, entries = analyzer_ternary.get_all_decomp_and_e_above_hull(te_entry)
     self.assertEqual(len(de), 116)
     self.assertEqual(len(hull_e), 116)
     self.assertAlmostEqual(hull_e[0], 29.2520325229)
示例#10
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 def test_ternary(self):
     # Ternary
     te_entry = self.multi_data['ternary'][20]
     pd_ternary = PourbaixDiagram(self.multi_data['ternary'],
                                  comp_dict = {"Ag": 0.33333, 
                                               "Te": 0.33333,
                                               "N": 0.33333})
     analyzer_ternary = PourbaixAnalyzer(pd_ternary)
     de, hull_e, entries = analyzer_ternary.get_all_decomp_and_e_above_hull(te_entry)
     self.assertEqual(len(de), 116)
     self.assertEqual(len(hull_e), 116)
     tuples = zip(de, hull_e, entries)
     test_tuple = [t for t in tuples if t[2].name=='N2(s) + TeO4[2-] + Ag[2+]'][0]
     self.assertAlmostEqual(test_tuple[1], 50.337069095866745)
示例#11
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    def test_plot_entry_stability(self):
        entry = self.pd.all_entries[0]
        plt = self.plotter.plot_entry_stability(entry,
                                                limits=[[-2, 14], [-3, 3]])

        # binary system
        pd_binary = PourbaixDiagram(self.multi_data['binary'],
                                    comp_dict={
                                        "Ag": 0.5,
                                        "Te": 0.5
                                    })
        binary_plotter = PourbaixPlotter(pd_binary)
        test_entry = pd_binary._unprocessed_entries[0]
        binary_plotter.plot_entry_stability(test_entry)
示例#12
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    def test_binary(self):
        # Test get_all_decomp_and_e_above_hull
        pd_binary = PourbaixDiagram(self.multi_data['binary'], 
                                    comp_dict = {"Ag": 0.5, "Te": 0.5})
        analyzer_binary = PourbaixAnalyzer(pd_binary)

        te_entry = [e for e in pd_binary._unprocessed_entries
                    if e.composition.formula == "Te3"][0]
        de, hull_e, entries = analyzer_binary.get_all_decomp_and_e_above_hull(te_entry)
        self.assertEqual(len(de), 10)
        self.assertEqual(len(hull_e), 10)
        # Find a specific multientry to test
        tuples = zip(de, hull_e, entries)
        test_tuple = [t for t in tuples if t[2].name=='Te(s) + Ag[2+]'][0]
        self.assertAlmostEqual(test_tuple[1], 5.1396968548627315)
def print_name(element1,element2,mat_co_1,entry):
    """
    Print entry name if single, else print multientry
    """
    str_name = ""
    entries= pd_entries(element1,element2)
    pourbaix = PourbaixDiagram(entries, {element1: mat_co_1, element2: 1- mat_co_1})
    pd = pourbaix
    if isinstance(entry, MultiEntry):
        if len(entry.entrylist) > 2:
            return str(pd.qhull_entries.index(entry))
        for e in entry.entrylist:
            str_name += (e.name) + " + "
        str_name = str_name[:-3]
        return str_name
    else:
        return entry.name
示例#14
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def phase_coord(entries, atom_comp, prim_elem=False):
    """
	Produces a list of line segments corresponding to each phase area in a PD
	along with the PD entries corresponding to each area.
	The produced list is of the following form:
		list = [[[coordinate data], [pourbaix entry]], [], [] .... ]

	Args:
		entries: List of entries in a PD
		atom_comp: Composition of atom if system is binary, given as a fraction
			between 0 and 1. Corresponds to the element with lowest atomic number if
			prim_elem is left to its default
		prim_elem: Primary element to which the atom_comp is assigned
	"""
    # | -  - phase_coord
    from pymatgen.analysis.pourbaix.maker import PourbaixDiagram
    from pymatgen.analysis.pourbaix.plotter import PourbaixPlotter
    from entry_methods import base_atom

    base_atoms = base_atom(entries)
    mat0 = base_atoms[0]
    if len(base_atoms) == 2: mat1 = base_atoms[1]
    else: mat1 = mat0

    # If the primary element is declared then set the given composition to it
    if not prim_elem == False:
        for atom in base_atoms:
            if atom == prim_elem:
                mat0 = atom
            else:
                mat1 = atom

    pd = PourbaixDiagram(entries, {mat0: atom_comp, mat1: 1 - atom_comp})
    pl = PourbaixPlotter(pd)
    ppd = pl.pourbaix_plot_data([[-2, 16], [-3,
                                            3]])  #ppd == Pourbaix_Plot Data
    pd_lst = []
    cnt = 0

    for stable_entry in ppd[0]:
        pd_lst.append([])
        pd_lst[cnt].append(ppd[0][stable_entry])
        pd_lst[cnt].append(stable_entry.entrylist)
        cnt = cnt + 1

    return pd_lst
def pourbaix_plot_data(element1,element2,mat_co_1,limits=None):
    """
    Get stable/unstable species required to plot Pourbaix diagram.

    Args:
        limits: 2D list containing limits of the Pourbaix diagram
            of the form [[xlo, xhi], [ylo, yhi]]

    Returns:
        stable_entries, unstable_entries
        stable_entries: dict of lines. The keys are Pourbaix Entries, and
        lines are in the form of a list
        unstable_entries: list of unstable entries
    """
    entries= pd_entries(element1,element2)
    pourbaix = PourbaixDiagram(entries, {element1: mat_co_1, element2: 1- mat_co_1})
    pd = pourbaix
    analyzer = PourbaixAnalyzer(pd)
#     self._analyzer = analyzer
    if limits:
        analyzer.chempot_limits = limits
    chempot_ranges = analyzer.get_chempot_range_map(limits)
#     self.chempot_ranges = chempot_ranges
    stable_entries_list = collections.defaultdict(list)

    for entry in chempot_ranges:
        for line in chempot_ranges[entry]:
            x = [line.coords[0][0], line.coords[1][0]]
            y = [line.coords[0][1], line.coords[1][1]]
            coords = [x, y]
            stable_entries_list[entry].append(coords)

    unstable_entries_list = [entry for entry in pd.all_entries
                             if entry not in pd.stable_entries]
    stable_entries_aq = []
    stable_entries_solid = []
    for entry in entries:
    	entry_kj_per_mol = entry.energy * 96.4853
    	if entry.phase_type == "Ion":
    		stable_entries_aq.append([entry.name,entry_kj_per_mol])
    	else:
    		stable_entries_solid.append([entry.name,entry_kj_per_mol])

    return stable_entries_list, unstable_entries_list, stable_entries_aq, stable_entries_solid
示例#16
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def oxidation_dissolution_product_0(i, j, scale):
	"""
	Creates Pourbaix Diagrams for single or binary systems
	"""
	#| -  - oxidation_dissolution_product_0
	# from pourdiag import pd_entries

	from pymatgen.analysis.pourbaix.maker import PourbaixDiagram
	from pymatgen.analysis.pourbaix.plotter import PourbaixPlotter
	from pd_screen_tools import phase_coord, phase_filter
	from stability_crit import most_stable_phase, oxidation_dissolution_product

	elem0 = i.symbol; elem1 = j.symbol

	mat_co_0 = 0.50		# Composition of 1st entry in elem_sys

	entr = pd_entries(elem0,elem1)
	pourbaix = PourbaixDiagram(entr,{elem0: mat_co_0,elem1: 1-mat_co_0})
	plotter = PourbaixPlotter(pourbaix)

	coord = phase_coord(entr,mat_co_0)
	filt1 = phase_filter(coord,'metallic')
	filt2 = phase_filter(coord,'metallic_metallic')
	filt = filt1 + filt2
	msp = most_stable_phase(filt,scale='RHE')

	tmp = oxidation_dissolution_product(coord,msp)

	if 'Ion' in tmp:
		entry_lst = 'dis'
	else:
		entry_lst = 'oxi'

	"""
	entry_lst = ''
	i_cnt = 0
	for i in tmp:
		entry_lst = str(entry_lst)+'\n'+str(i)
		if i_cnt==0:
			entry_lst = entry_lst[1:]
		i_cnt=i_cnt+1

	"""
	return entry_lst
示例#17
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def phase_coord(entries, atom_comp, prim_elem=None):
    """Produces a list of line segments corresponding to each phase area in a PD
    along with the PD entries corresponding to each area.
    The produced list is of the following form:
        list = [[[coordinate data], [pourbaix entry]], [], [] .... ]

    Parameters:
    -----------
    entries: list
        entries in a PD
    atom_comp: float
        Composition of atom if system is binary, given as a fraction
        between 0 and 1. Corresponds to the element with lowest atomic
        number if prim_elem is left to its default
    prim_elem: str
        Primary element to which the atom_comp is assigned
    """
    base_atoms = base_atom(entries)
    mat0 = base_atoms[0]
    if len(base_atoms) == 2:
        mat1 = base_atoms[1]
    else:
        mat1 = mat0

    if prim_elem:
        for atom in base_atoms:
            if atom == prim_elem:
                mat0 = atom
            else:
                mat1 = atom

    pd = PourbaixDiagram(entries, {mat0: atom_comp, mat1: 1 - atom_comp})
    pl = PourbaixPlotter(pd)
    ppd = pl.pourbaix_plot_data([[-2, 16], [-3, 3]])

    pd_lst = []
    for i, stable_entry in enumerate(ppd[0]):
        pd_lst += [[]]
        pd_lst[i] += [ppd[0][stable_entry]]
        if isinstance(stable_entry, PourbaixEntry):
            pd_lst[i] += [stable_entry]
        else:
            pd_lst[i] += [stable_entry.entrylist]
    return pd_lst
示例#18
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def is_solid_phase(mat1, mat2, mat1_co=0.5):
    """
	Returns TRUE is there exists a all solid phase in the binary Pourbaix Diagram
	This means that the phase doesn't have any aqueous species

	Args:
		mat1:
		mat2:
		mat1_co:
	"""

    # | -  - is_solid_phase
    from pourdiag import pourdiag  # Returns Pourbaix entries for binary system
    from pymatgen.analysis.pourbaix.maker import PourbaixDiagram
    from pymatgen.analysis.pourbaix.plotter import PourbaixPlotter

    mat2_co = 1 - mat1_co

    pd_b = pourdiag(mat1, mat2)
    return pd_b

    pd = PourbaixDiagram(pd_b, {mat1: mat1_co, mat2: mat2_co})
    pl = PourbaixPlotter(pd)
    ppd = pl.pourbaix_plot_data([[-2, 16], [-3,
                                            3]])  #ppd == Pourbaix_Plot Data

    pd_lst = []
    cnt = 0
    for stable_entry in ppd[0]:
        pd_lst.append([])
        pd_lst[cnt].append(ppd[0][stable_entry])
        pd_lst[cnt].append(stable_entry.entrylist)
        cnt = cnt + 1

    solidphase = False
    for i in pd_lst:
        if len(i[1]) == 1:
            if i[1][0].phase_type == 'Solid':
                solidphase = True
        if len(i[1]) == 2:
            if i[1][0].phase_type and i[1][1].phase_type == 'Solid':
                solidphase = True
    return solidphase
示例#19
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 def setUp(self):
     module_dir = os.path.dirname(os.path.abspath(__file__))
     (elements, entries) = PourbaixEntryIO.from_csv(
         os.path.join(module_dir, "test_entries.csv"))
     self.num_simplices = {
         "Zn(s)": 7,
         "ZnO2(s)": 7,
         "Zn[2+]": 4,
         "ZnO2[2-]": 4,
         "ZnHO2[-]": 4
     }
     self.e_above_hull_test = {"ZnHO[+]": 0.0693, "ZnO(aq)": 0.0624}
     self.decomp_test = {
         "ZnHO[+]": {
             "ZnO(s)": 0.5,
             "Zn[2+]": 0.5
         },
         "ZnO(aq)": {
             "ZnO(s)": 1.0
         }
     }
     self.pd = PourbaixDiagram(entries)
     self.plotter = PourbaixPlotter(self.pd)
示例#20
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def plot_pourbaix_diagram(metastability=0.0, ion_concentration=1e-6, fmt='pdf'):
    """
    Creates a Pourbaix diagram for the material in the cwd.

    Args:
        metastability (float): desired metastable tolerance energy
            (meV/atom). <~50 is generally a sensible range to use.
        ion_concentration (float): in mol/kg. Sensible values are
            generally between 1e-8 and 1.
        fmt (str): matplotlib format style. Check the matplotlib
            docs for options.
    """

    # Create a ComputedEntry object for the 2D material.
    composition = Structure.from_file('POSCAR').composition
    energy = Vasprun('vasprun.xml').final_energy

    cmpd = ComputedEntry(composition, energy)

    # Define the chemsys that describes the 2D compound.
    chemsys = ['O', 'H'] + [elt.symbol for elt in composition.elements
                            if elt.symbol not in ['O', 'H']]

    # Pick out the ions pertaining to the 2D compound.
    ion_dict = dict()
    for elt in chemsys:
        if elt not in ['O', 'H'] and ION_FORMATION_ENERGIES[elt]:
            ion_dict.update(ION_FORMATION_ENERGIES[elt])

    elements = [Element(elt) for elt in chemsys if elt not in ['O', 'H']]

    # Add "correction" for metastability
    cmpd.correction -= float(cmpd.composition.num_atoms)\
        * float(metastability) / 1000.0

    # Calculate formation energy of the compound from its end
    # members
    form_energy = cmpd.energy
    for elt in composition.as_dict():
        form_energy -= CHEMICAL_POTENTIALS[elt] * cmpd.composition[elt]

    # Convert the compound entry to a pourbaix entry.
    # Default concentration for solid entries = 1
    pbx_cmpd = PourbaixEntry(cmpd)
    pbx_cmpd.g0_replace(form_energy)
    pbx_cmpd.reduced_entry()

    # Add corrected ionic entries to the pourbaix diagram
    # dft corrections for experimental ionic energies:
    # Persson et.al PHYSICAL REVIEW B 85, 235438 (2012)
    pbx_ion_entries = list()

    # Get PourbaixEntry corresponding to each ion.
    # Default concentration for ionic entries = 1e-6
    # ion_energy = ion_exp_energy + ion_correction * factor
    # where factor = fraction of element el in the ionic entry
    # compared to the reference entry
    for elt in elements:
        for key in ion_dict:
            comp = Ion.from_formula(key)
            if comp.composition[elt] != 0:
                factor = comp.composition[elt]
                energy = ion_dict[key]
                pbx_entry_ion = PourbaixEntry(IonEntry(comp, energy))
                pbx_entry_ion.correction = (
                    ION_CORRECTIONS[elt.symbol] * factor
                )
                pbx_entry_ion.conc = ion_concentration
                pbx_entry_ion.name = key
                pbx_ion_entries.append(pbx_entry_ion)

    # Generate and plot Pourbaix diagram
    # Each bulk solid/ion has a free energy g of the form:
    # g = g0_ref + 0.0591 * log10(conc) - nO * mu_H2O +
    # (nH - 2nO) * pH + phi * (-nH + 2nO + q)

    all_entries = [pbx_cmpd] + pbx_ion_entries

    total = sum([composition[el] for el in elements])
    comp_dict = {el.symbol: composition[el]/total for el in elements}
    pourbaix_diagram = PourbaixDiagram(all_entries, comp_dict=comp_dict)

    plotter = PourbaixPlotter(pourbaix_diagram)

    # Plotting details...
    font = "serif"
    fig = plt.figure(figsize=(14, 9))
    ax1 = fig.gca()
    ax1.set_xlim([0, 14])
    ax1.set_xticklabels([int(t) for t in ax1.get_xticks()], fontname=font,
                        fontsize=18)
    ax1.set_ylim(-2, 2)
    ax1.set_yticklabels(ax1.get_yticks(), fontname=font, fontsize=18)
    ax1.set_xlabel("pH", fontname=font, fontsize=18)
    ax1.set_ylabel("Potential vs. SHE (V)", fontname=font, fontsize=18)

    # Outline water's stability range.
    ax1.plot([0, 14], [0, -0.829], color="gray", linestyle="--", alpha=0.7,
             linewidth=2)
    ax1.plot([0, 14], [1.229, 0.401], color="gray", linestyle="--", alpha=0.7,
             linewidth=2)


    stable_entries = plotter.pourbaix_plot_data(
        limits=[[0, 14], [-2, 2]])[0]

    # Add coloring.
    colors = sb.color_palette("Set2", len(stable_entries))

    i = 0
    for entry in stable_entries:
        col = colors[i]
        i += 1
        vertices = plotter.domain_vertices(entry)
        center_x = sum([v[0] for v in vertices])/len(vertices)
        center_y = sum([v[1] for v in vertices])/len(vertices)
        patch = Polygon(vertices, closed=True, fill=True, facecolor=col,
                        linewidth=2, edgecolor="w")
        ax1.text(center_x, center_y, plotter.print_name(entry),
                 verticalalignment="center", horizontalalignment="center",
                 fontname=font, fontsize=18)
        ax1.add_patch(patch)

    plt.savefig("pourbaix.{}".format(fmt))

    plt.close()
示例#21
0
 def setUp(self):
     module_dir = os.path.dirname(os.path.abspath(__file__))
     (elements, entries) = PourbaixEntryIO.from_csv(
         os.path.join(module_dir, "test_entries.csv"))
     self._entries = entries
     self._pd = PourbaixDiagram(entries)
示例#22
0
def plot_pourbaix_diagram(metastability=0.0,
                          ion_concentration=1e-6,
                          fmt='pdf'):
    """
    Creates a Pourbaix diagram for the material in the cwd.

    Args:
        metastability (float): desired metastable tolerance energy
            (meV/atom). <~50 is generally a sensible range to use.
        ion_concentration (float): in mol/kg. Sensible values are
            generally between 1e-8 and 1.
        fmt (str): matplotlib format style. Check the matplotlib
            docs for options.
    """

    # Create a ComputedEntry object for the 2D material.
    composition = Structure.from_file('POSCAR').composition
    energy = Vasprun('vasprun.xml').final_energy

    cmpd = ComputedEntry(composition, energy)

    # Define the chemsys that describes the 2D compound.
    chemsys = ['O', 'H'] + [
        elt.symbol
        for elt in composition.elements if elt.symbol not in ['O', 'H']
    ]

    # Pick out the ions pertaining to the 2D compound.
    ion_dict = dict()
    for elt in chemsys:
        if elt not in ['O', 'H'] and ION_FORMATION_ENERGIES[elt]:
            ion_dict.update(ION_FORMATION_ENERGIES[elt])

    elements = [Element(elt) for elt in chemsys if elt not in ['O', 'H']]

    # Add "correction" for metastability
    cmpd.correction -= float(cmpd.composition.num_atoms)\
        * float(metastability) / 1000.0

    # Calculate formation energy of the compound from its end
    # members
    form_energy = cmpd.energy
    for elt in composition.as_dict():
        form_energy -= CHEMICAL_POTENTIALS[elt] * cmpd.composition[elt]

    # Convert the compound entry to a pourbaix entry.
    # Default concentration for solid entries = 1
    pbx_cmpd = PourbaixEntry(cmpd)
    pbx_cmpd.g0_replace(form_energy)
    pbx_cmpd.reduced_entry()

    # Add corrected ionic entries to the pourbaix diagram
    # dft corrections for experimental ionic energies:
    # Persson et.al PHYSICAL REVIEW B 85, 235438 (2012)
    pbx_ion_entries = list()

    # Get PourbaixEntry corresponding to each ion.
    # Default concentration for ionic entries = 1e-6
    # ion_energy = ion_exp_energy + ion_correction * factor
    # where factor = fraction of element el in the ionic entry
    # compared to the reference entry
    for elt in elements:
        for key in ion_dict:
            comp = Ion.from_formula(key)
            if comp.composition[elt] != 0:
                factor = comp.composition[elt]
                energy = ion_dict[key]
                pbx_entry_ion = PourbaixEntry(IonEntry(comp, energy))
                pbx_entry_ion.correction = (ION_CORRECTIONS[elt.symbol] *
                                            factor)
                pbx_entry_ion.conc = ion_concentration
                pbx_entry_ion.name = key
                pbx_ion_entries.append(pbx_entry_ion)

    # Generate and plot Pourbaix diagram
    # Each bulk solid/ion has a free energy g of the form:
    # g = g0_ref + 0.0591 * log10(conc) - nO * mu_H2O +
    # (nH - 2nO) * pH + phi * (-nH + 2nO + q)

    all_entries = [pbx_cmpd] + pbx_ion_entries

    pourbaix = PourbaixDiagram(all_entries)

    # Analysis features
    # panalyzer = PourbaixAnalyzer(pourbaix)
    # instability = panalyzer.get_e_above_hull(pbx_cmpd)

    plotter = PourbaixPlotter(pourbaix)
    plot = plotter.get_pourbaix_plot(limits=[[0, 14], [-2, 2]],
                                     label_domains=True)
    fig = plot.gcf()
    ax1 = fig.gca()

    # Add coloring to highlight the stability region for the 2D
    # material, if one exists.
    stable_entries = plotter.pourbaix_plot_data(limits=[[0, 14], [-2, 2]])[0]

    for entry in stable_entries:
        if entry == pbx_cmpd:
            col = plt.cm.Blues(0)
        else:
            col = plt.cm.rainbow(
                float(ION_COLORS[entry.composition.reduced_formula]))

        vertices = plotter.domain_vertices(entry)
        patch = Polygon(vertices, closed=True, fill=True, color=col)
        ax1.add_patch(patch)

    fig.set_size_inches((11.5, 9))
    plot.tight_layout(pad=1.09)

    # Save plot
    if metastability:
        plot.suptitle('Metastable Tolerance ='
                      ' {} meV/atom'.format(metastability),
                      fontsize=20)
        plot.savefig('{}_{}.{}'.format(composition.reduced_formula,
                                       ion_concentration, fmt),
                     transparent=True)
    else:
        plot.savefig('{}_{}.{}'.format(composition.reduced_formula,
                                       ion_concentration, fmt),
                     transparent=True)

    plot.close()