/usr/share/pyshared/ase/lattice/surface.py is in python-ase 3.6.0.2515-1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 | """Helper functions for creating the most common surfaces and related tasks.
The helper functions can create the most common low-index surfaces,
add vacuum layers and add adsorbates.
"""
from math import sqrt
import numpy as np
from ase.atom import Atom
from ase.atoms import Atoms
from ase.data import reference_states, atomic_numbers
from ase.lattice.general_surface import surface
def fcc100(symbol, size, a=None, vacuum=None):
"""FCC(100) surface.
Supported special adsorption sites: 'ontop', 'bridge', 'hollow'."""
return _surface(symbol, 'fcc', '100', size, a, None, vacuum)
def fcc110(symbol, size, a=None, vacuum=None):
"""FCC(110) surface.
Supported special adsorption sites: 'ontop', 'longbridge',
'shortbridge','hollow'."""
return _surface(symbol, 'fcc', '110', size, a, None, vacuum)
def bcc100(symbol, size, a=None, vacuum=None):
"""BCC(100) surface.
Supported special adsorption sites: 'ontop', 'bridge', 'hollow'."""
return _surface(symbol, 'bcc', '100', size, a, None, vacuum)
def bcc110(symbol, size, a=None, vacuum=None, orthogonal=False):
"""BCC(110) surface.
Supported special adsorption sites: 'ontop', 'longbridge',
'shortbridge', 'hollow'.
Use *orthogonal=True* to get an orthogonal unit cell - works only
for size=(i,j,k) with j even."""
return _surface(symbol, 'bcc', '110', size, a, None, vacuum, orthogonal)
def bcc111(symbol, size, a=None, vacuum=None, orthogonal=False):
"""BCC(111) surface.
Supported special adsorption sites: 'ontop'.
Use *orthogonal=True* to get an orthogonal unit cell - works only
for size=(i,j,k) with j even."""
return _surface(symbol, 'bcc', '111', size, a, None, vacuum, orthogonal)
def fcc111(symbol, size, a=None, vacuum=None, orthogonal=False):
"""FCC(111) surface.
Supported special adsorption sites: 'ontop', 'bridge', 'fcc' and 'hcp'.
Use *orthogonal=True* to get an orthogonal unit cell - works only
for size=(i,j,k) with j even."""
return _surface(symbol, 'fcc', '111', size, a, None, vacuum, orthogonal)
def hcp0001(symbol, size, a=None, c=None, vacuum=None, orthogonal=False):
"""HCP(0001) surface.
Supported special adsorption sites: 'ontop', 'bridge', 'fcc' and 'hcp'.
Use *orthogonal=True* to get an orthogonal unit cell - works only
for size=(i,j,k) with j even."""
return _surface(symbol, 'hcp', '0001', size, a, c, vacuum, orthogonal)
def hcp10m10(symbol, size, a=None, c=None, vacuum=None):
"""HCP(10m10) surface.
Supported special adsorption sites: 'ontop'.
Works only for size=(i,j,k) with j even."""
return _surface(symbol, 'hcp', '10m10', size, a, c, vacuum)
def diamond100(symbol, size, a=None, vacuum=None):
"""DIAMOND(100) surface.
Supported special adsorption sites: 'ontop'."""
return _surface(symbol, 'diamond', '100', size, a, None, vacuum)
def diamond111(symbol, size, a=None, vacuum=None, orthogonal=False):
"""DIAMOND(111) surface.
Supported special adsorption sites: 'ontop'."""
if orthogonal:
raise NotImplementedError("Can't do orthogonal cell yet!")
return _surface(symbol, 'diamond', '111', size, a, None, vacuum, orthogonal)
def add_adsorbate(slab, adsorbate, height, position=(0, 0), offset=None,
mol_index=0):
"""Add an adsorbate to a surface.
This function adds an adsorbate to a slab. If the slab is
produced by one of the utility functions in ase.lattice.surface, it
is possible to specify the position of the adsorbate by a keyword
(the supported keywords depend on which function was used to
create the slab).
If the adsorbate is a molecule, the atom indexed by the mol_index
optional argument is positioned on top of the adsorption position
on the surface, and it is the responsibility of the user to orient
the adsorbate in a sensible way.
This function can be called multiple times to add more than one
adsorbate.
Parameters:
slab: The surface onto which the adsorbate should be added.
adsorbate: The adsorbate. Must be one of the following three types:
A string containing the chemical symbol for a single atom.
An atom object.
An atoms object (for a molecular adsorbate).
height: Height above the surface.
position: The x-y position of the adsorbate, either as a tuple of
two numbers or as a keyword (if the surface is produced by one
of the functions in ase.lattice.surfaces).
offset (default: None): Offsets the adsorbate by a number of unit
cells. Mostly useful when adding more than one adsorbate.
mol_index (default: 0): If the adsorbate is a molecule, index of
the atom to be positioned above the location specified by the
position argument.
Note *position* is given in absolute xy coordinates (or as
a keyword), whereas offset is specified in unit cells. This
can be used to give the positions in units of the unit cell by
using *offset* instead.
"""
info = slab.adsorbate_info
if 'cell' not in info:
info['cell'] = slab.get_cell()[:2, :2]
pos = np.array([0.0, 0.0]) # (x, y) part
spos = np.array([0.0, 0.0]) # part relative to unit cell
if offset is not None:
spos += np.asarray(offset, float)
if isinstance(position, str):
# A site-name:
if 'sites' not in info:
raise TypeError('If the atoms are not made by an ' +
'ase.lattice.surface function, ' +
'position cannot be a name.')
if position not in info['sites']:
raise TypeError('Adsorption site %s not supported.' % position)
spos += info['sites'][position]
else:
pos += position
pos += np.dot(spos, info['cell'])
# Convert the adsorbate to an Atoms object
if isinstance(adsorbate, Atoms):
ads = adsorbate
elif isinstance(adsorbate, Atom):
ads = Atoms([adsorbate])
else:
# Hope it is a useful string or something like that
ads = Atoms(adsorbate)
# Get the z-coordinate:
try:
a = info['top layer atom index']
except KeyError:
a = slab.positions[:, 2].argmax()
info['top layer atom index'] = a
z = slab.positions[a, 2] + height
# Move adsorbate into position
ads.translate([pos[0], pos[1], z] - ads.positions[mol_index])
# Attach the adsorbate
slab.extend(ads)
def _surface(symbol, structure, face, size, a, c, vacuum, orthogonal=True):
"""Function to build often used surfaces.
Don't call this function directly - use fcc100, fcc110, bcc111, ..."""
Z = atomic_numbers[symbol]
if a is None:
sym = reference_states[Z]['symmetry']
if sym != structure:
raise ValueError("Can't guess lattice constant for %s-%s!" %
(structure, symbol))
a = reference_states[Z]['a']
if structure == 'hcp' and c is None:
if reference_states[Z]['symmetry'] == 'hcp':
c = reference_states[Z]['c/a'] * a
else:
c = sqrt(8 / 3.0) * a
positions = np.empty((size[2], size[1], size[0], 3))
positions[..., 0] = np.arange(size[0]).reshape((1, 1, -1))
positions[..., 1] = np.arange(size[1]).reshape((1, -1, 1))
positions[..., 2] = np.arange(size[2]).reshape((-1, 1, 1))
numbers = np.ones(size[0] * size[1] * size[2], int) * Z
tags = np.empty((size[2], size[1], size[0]), int)
tags[:] = np.arange(size[2], 0, -1).reshape((-1, 1, 1))
slab = Atoms(numbers,
tags=tags.ravel(),
pbc=(True, True, False),
cell=size)
surface_cell = None
sites = {'ontop': (0, 0)}
surf = structure + face
if surf == 'fcc100':
cell = (sqrt(0.5), sqrt(0.5), 0.5)
positions[-2::-2, ..., :2] += 0.5
sites.update({'hollow': (0.5, 0.5), 'bridge': (0.5, 0)})
elif surf == 'diamond100':
cell = (sqrt(0.5), sqrt(0.5), 0.5 / 2)
positions[-4::-4, ..., :2] += (0.5, 0.5)
positions[-3::-4, ..., :2] += (0.0, 0.5)
positions[-2::-4, ..., :2] += (0.0, 0.0)
positions[-1::-4, ..., :2] += (0.5, 0.0)
elif surf == 'fcc110':
cell = (1.0, sqrt(0.5), sqrt(0.125))
positions[-2::-2, ..., :2] += 0.5
sites.update({'hollow': (0.5, 0.5), 'longbridge': (0.5, 0),
'shortbridge': (0, 0.5)})
elif surf == 'bcc100':
cell = (1.0, 1.0, 0.5)
positions[-2::-2, ..., :2] += 0.5
sites.update({'hollow': (0.5, 0.5), 'bridge': (0.5, 0)})
else:
if orthogonal and size[1] % 2 == 1:
raise ValueError(("Can't make orthorhombic cell with size=%r. " %
(tuple(size),)) +
'Second number in size must be even.')
if surf == 'fcc111':
cell = (sqrt(0.5), sqrt(0.375), 1 / sqrt(3))
if orthogonal:
positions[-1::-3, 1::2, :, 0] += 0.5
positions[-2::-3, 1::2, :, 0] += 0.5
positions[-3::-3, 1::2, :, 0] -= 0.5
positions[-2::-3, ..., :2] += (0.0, 2.0 / 3)
positions[-3::-3, ..., :2] += (0.5, 1.0 / 3)
else:
positions[-2::-3, ..., :2] += (-1.0 / 3, 2.0 / 3)
positions[-3::-3, ..., :2] += (1.0 / 3, 1.0 / 3)
sites.update({'bridge': (0.5, 0), 'fcc': (1.0 / 3, 1.0 / 3),
'hcp': (2.0 / 3, 2.0 / 3)})
elif surf == 'diamond111':
cell = (sqrt(0.5), sqrt(0.375), 1 / sqrt(3) / 2)
assert not orthogonal
positions[-1::-6, ..., :3] += (0.0, 0.0, 0.5)
positions[-2::-6, ..., :2] += (0.0, 0.0)
positions[-3::-6, ..., :3] += (-1.0 / 3, 2.0 / 3, 0.5)
positions[-4::-6, ..., :2] += (-1.0 / 3, 2.0 / 3)
positions[-5::-6, ..., :3] += (1.0 / 3, 1.0 / 3, 0.5)
positions[-6::-6, ..., :2] += (1.0 / 3, 1.0 / 3)
elif surf == 'hcp0001':
cell = (1.0, sqrt(0.75), 0.5 * c / a)
if orthogonal:
positions[:, 1::2, :, 0] += 0.5
positions[-2::-2, ..., :2] += (0.0, 2.0 / 3)
else:
positions[-2::-2, ..., :2] += (-1.0 / 3, 2.0 / 3)
sites.update({'bridge': (0.5, 0), 'fcc': (1.0 / 3, 1.0 / 3),
'hcp': (2.0 / 3, 2.0 / 3)})
elif surf == 'hcp10m10':
cell = (1.0, 0.5 * c / a, sqrt(0.75))
assert orthogonal
positions[-2::-2, ..., 0] += 0.5
positions[:, ::2, :, 2] += 2.0 / 3
elif surf == 'bcc110':
cell = (1.0, sqrt(0.5), sqrt(0.5))
if orthogonal:
positions[:, 1::2, :, 0] += 0.5
positions[-2::-2, ..., :2] += (0.0, 1.0)
else:
positions[-2::-2, ..., :2] += (-0.5, 1.0)
sites.update({'shortbridge': (0, 0.5),
'longbridge': (0.5, 0),
'hollow': (0.375, 0.25)})
elif surf == 'bcc111':
cell = (sqrt(2), sqrt(1.5), sqrt(3) / 6)
if orthogonal:
positions[-1::-3, 1::2, :, 0] += 0.5
positions[-2::-3, 1::2, :, 0] += 0.5
positions[-3::-3, 1::2, :, 0] -= 0.5
positions[-2::-3, ..., :2] += (0.0, 2.0 / 3)
positions[-3::-3, ..., :2] += (0.5, 1.0 / 3)
else:
positions[-2::-3, ..., :2] += (-1.0 / 3, 2.0 / 3)
positions[-3::-3, ..., :2] += (1.0 / 3, 1.0 / 3)
sites.update({'hollow': (1.0 / 3, 1.0 / 3)})
else:
2 / 0
surface_cell = a * np.array([(cell[0], 0),
(cell[0] / 2, cell[1])])
if not orthogonal:
cell = np.array([(cell[0], 0, 0),
(cell[0] / 2, cell[1], 0),
(0, 0, cell[2])])
if surface_cell is None:
surface_cell = a * np.diag(cell[:2])
if isinstance(cell, tuple):
cell = np.diag(cell)
slab.set_positions(positions.reshape((-1, 3)))
slab.set_cell([a * v * n for v, n in zip(cell, size)], scale_atoms=True)
if vacuum is not None:
slab.center(vacuum=vacuum, axis=2)
slab.adsorbate_info['cell'] = surface_cell
slab.adsorbate_info['sites'] = sites
return slab
|