Source code for sknano.structures._swnt
# -*- coding: utf-8 -*-
"""
==============================================================================
SWNT structure class (:mod:`sknano.structures._swnt`)
==============================================================================
.. currentmodule:: sknano.structures._swnt
"""
from __future__ import absolute_import, division, print_function, \
unicode_literals
__docformat__ = 'restructuredtext en'
from ._base import StructureBase
from ._compute_funcs import compute_tube_mass, compute_linear_mass_density
from ._extras import attr_strfmt, attr_symbols, attr_units
from ._mixins import NanotubeMixin
__all__ = ['SWNT', 'Nanotube']
[docs]class SWNT(NanotubeMixin, StructureBase):
"""SWNT structure class.
Parameters
----------
n, m : int
Chiral indices defining the nanotube chiral vector
:math:`\\mathbf{C}_h = n\\mathbf{a}_1 + m\\mathbf{a}_2 = (n, m)`.
nz : int, optional
Number of repeat unit cells along the :math:`z` dimension
element1, element2 : {str, int}, optional
Element symbol or atomic number of basis
:class:`~sknano.core.atoms.Atom` 1 and 2
bond : float, optional
Distance between nearest neighbor atoms (i.e., bond length).
Must be in units of **\u212b**. Default value is
the carbon-carbon bond length in graphite, approximately
:math:`\\mathrm{a}_{\\mathrm{CC}} = 1.42` \u212b
Lz : float, optional
Length of the nanotube in **nanometers**.
Overrides the :math:`n_z` cell values.
.. versionadded:: 0.2.5
tube_length : float, optional
Length of nanotube in units of **nanometers**.
Overrides `nz` value.
.. deprecated:: 0.2.5
Use `Lz` instead
fix_Lz : bool, optional
Generate the nanotube with length as close to the specified
:math:`L_z` as possible. If `True`, then
non integer :math:`n_z` cells are permitted.
Examples
--------
>>> from sknano.structures import SWNT
Create a SWNT with :math:`\\mathbf{C}_{h} = (10, 10)` chirality.
>>> swnt = SWNT(n=10, m=10, verbose=True)
>>> print(unicode(swnt))
SWNT(n=10, m=10, element1='C', element2='C', bond=1.42, nz=1)
n: 10
m: 10
t₁: 1
t₂: -1
d: 10
dR: 30
N: 20
R: (1, 0)
θc: 30.00°
Ch: 42.60 Å
T: 2.46 Å
dt: 13.56 Å
rt: 6.78 Å
electronic_type: metallic
Change the chirality to :math:`\\mathbf{C}_{h} = (20, 10)`.
>>> swnt.n = 20
>>> print(unicode(swnt))
SWNT(n=20, m=10, element1='C', element2='C', bond=1.42, nz=1)
n: 20
m: 10
t₁: 4
t₂: -5
d: 10
dR: 10
N: 140
R: (1, -1)
θc: 19.11°
Ch: 65.07 Å
T: 11.27 Å
dt: 20.71 Å
rt: 10.36 Å
electronic_type: semiconducting, type 2
Change the chirality to :math:`\\mathbf{C}_{h} = (20, 0)`.
>>> swnt.m = 0
>>> print(unicode(swnt))
SWNT(n=20, m=0, element1='C', element2='C', bond=1.42, nz=1)
n: 20
m: 0
t₁: 1
t₂: -2
d: 20
dR: 20
N: 40
R: (1, -1)
θc: 0.00°
Ch: 49.19 Å
T: 4.26 Å
dt: 15.66 Å
rt: 7.83 Å
electronic_type: semiconducting, type 1
"""
# add each attribute in the order I want them to appear in
# verbose output mode
_structure_attrs = ['n', 'm', 't1', 't2', 'd', 'dR', 'N', 'R',
'chiral_angle', 'Ch', 'T', 'dt', 'rt',
'electronic_type']
def __init__(self, n=10, m=0, nz=1, tube_length=None, Lz=None,
fix_Lz=False, **kwargs):
super(SWNT, self).__init__(**kwargs)
if tube_length is not None and Lz is None:
Lz = tube_length
self.L0 = Lz # store initial value of Lz
self.n = n
self.m = m
self.fix_Lz = fix_Lz
if Lz is not None:
self.nz = 10 * float(Lz) / self.T
elif nz is not None:
self.nz = nz
else:
self.nz = 1
def __str__(self):
"""Return nice string representation of `SWNT`."""
if self.verbose:
strrep = repr(self) + '\n'
for attr in self._structure_attrs:
var = attr
if attr in attr_symbols:
var = attr_symbols[attr]
if attr in attr_strfmt:
if attr in attr_units:
strrep += \
"{}: {}{}\n".format(
var, attr_strfmt[attr].format(
getattr(self, attr)), attr_units[attr])
else:
strrep += "{}: {}\n".format(
var, attr_strfmt[attr].format(getattr(self, attr)))
else:
if attr in attr_units:
strrep += "{}: {}{}\n".format(
var, getattr(self, attr), attr_units[attr])
else:
strrep += "{}: {}\n".format(
var, getattr(self, attr))
return strrep
def __repr__(self):
"""Return canonical string representation of `SWNT`."""
strrep = "SWNT(n={!r}, m={!r}, element1={!r}, element2={!r}, bond={!r}"
if self.fix_Lz:
strrep += ", Lz={!r}, fix_Lz={!r})"
return strrep.format(self.n, self.m, self.element1, self.element2,
self.bond, self.Lz, self.fix_Lz)
else:
strrep += ", nz={!r})"
return strrep.format(self.n, self.m, self.element1, self.element2,
self.bond, self.nz)
@property
def Natoms_per_tube(self):
"""Number of atoms in nanotube :math:`N_{\\mathrm{atoms/tube}}`."""
return self.Natoms
@property
def linear_mass_density(self):
"""Linear mass density of nanotube in g/nm."""
return compute_linear_mass_density(self.n, self.m, bond=self.bond,
element1=self.element1,
element2=self.element2)
@property
def Ntubes(self):
"""Number of nanotubes."""
return 1
@property
def tube_length(self):
"""Alias for :attr:`SWNT.Lz`"""
return self.Lz
@property
def tube_mass(self):
"""SWNT mass in **grams**."""
return compute_tube_mass(self.n, self.m, self.nz,
element1=self.element1,
element2=self.element2)
[docs] def todict(self):
"""Return :class:`~python:dict` of `SWNT` attributes."""
return dict(n=self.n, m=self.m, nz=self.nz, Lz=self.Lz,
fix_Lz=self.fix_Lz, element1=self.element1,
element2=self.element2, bond=self.bond)
Nanotube = SWNT