class sknano.structures.SWNT(*Ch, *, nz=None, basis=['C', 'C'], bond=1.42, gutter=None, Lz=None, fix_Lz=False, wrap_coords=False, **kwargs)[source][source]

SWNT structure class.


*Ch : {tuple or ints}

Either a 2-tuple of integers (i.e., *Ch = ((n, m)) or 2 integers (i.e., *Ch = (n, m) specifying the chiral indices of the nanotube chiral vector \(\mathbf{C}_h = n\mathbf{a}_1 + m\mathbf{a}_2 = (n, m)\).

nz : int, optional

Number of repeat unit cells in the \(z\) direction, along the length of the nanotube.

basis : {list}, optional

List of strs of element symbols or atomic number of the two atom basis (default: [‘C’, ‘C’])

New in version 0.3.10.

element1, element2 : {str, int}, optional

Element symbol or atomic number of basis Atom 1 and 2

Deprecated since version 0.3.10: Use basis instead

bond : float, optional

\(\mathrm{a}_{\mathrm{CC}} =\) distance between nearest neighbor atoms. Must be in units of Angstroms.

Lz : float, optional

Length of nanotube in units of nanometers. Overrides the nz value.

New in version 0.2.5.

tube_length : float, optional

Length of nanotube in units of nanometers. Overrides the nz value.

Deprecated since version 0.2.5: Use Lz instead

fix_Lz : bool, optional

Generate the nanotube with length as close to the specified \(L_z\) as possible. If True, then non integer \(n_z\) cells are permitted.

New in version 0.2.6.

verbose : bool, optional

if True, show verbose output


>>> from sknano.structures import SWNT

Create a SWNT with \(\mathbf{C}_{h} = (10, 10)\) chirality.

>>> swnt = SWNT((10, 10), verbose=True)
>>> print(swnt)
SWNT((10, 10), 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 \(\mathbf{C}_{h} = (20, 10)\).

>>> swnt.n = 20
>>> print(swnt)
SWNT((20, 10), 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 \(\mathbf{C}_{h} = (20, 0)\).

>>> swnt.m = 0
>>> print(swnt)
SWNT((20, 0), 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


Ch SWNT circumference \(|\mathbf{C}_h|\) in
Ch_vec SWNT chiral vector.
Lz SWNT length \(L_z = L_{\mathrm{tube}}\) in nanometers.
M \(M = np - nq\)
N Number of graphene hexagons in nanotube unit cell.
Natoms Number of atoms in nanotube.
Natoms_per_tube Number of atoms in nanotube \(N_{\mathrm{atoms/tube}}\).
Natoms_per_unit_cell Number of atoms in nanotube unit cell.
Ntubes Number of nanotubes.
R Symmetry vector \(\mathbf{R} = (p, q)\).
T Length of nanotube unit cell \(|\mathbf{T}|\) in Å.
Tvec SWNT translation vector.
atoms Structure StructureAtoms.
basis NanoStructureBase basis atoms.
chiral_angle Chiral angle \(\theta_c\) in degrees.
chiral_type SWNT chiral type.
crystal_cell Structure CrystalCell.
d \(d=\gcd{(n, m)}\)
dR \(d_R=\gcd{(2n + m, 2m + n)}\)
dt Nanotube diameter \(d_t = \frac{|\mathbf{C}_h|}{\pi}\) in Å.
electronic_type SWNT electronic type.
element1 Basis element 1
element2 Basis element 2
fmtstr Format string.
lattice Structure Crystal3DLattice.
linear_mass_density Linear mass density of nanotube in g/nm.
m Chiral index \(m\).
n Chiral index \(n\).
nz Number of nanotube unit cells along the \(z\)-axis.
rt Nanotube radius \(r_t = \frac{|\mathbf{C}_h|}{2\pi}\) in Å.
scaling_matrix CrystalCell.scaling_matrix.
structure Pointer to self.
structure_data Alias for BaseStructureMixin.structure.
t1 \(t_{1} = \frac{2m + n}{d_{R}}\)
t2 \(t_2 = -\frac{2n + m}{d_R}\)
tube_length Alias for SWNT.Lz
tube_mass SWNT mass in grams.
unit_cell Structure UnitCell.
unit_cell_mass Unit cell mass in atomic mass units.
unit_cell_symmetry_params Tuple of SWNT unit cell symmetry parameters.
vdw_distance van der Waals distance.
vdw_radius van der Waals radius


clear() Clear list of BaseStructureMixin.atoms.
generate_unit_cell() Generate the nanotube unit cell.
make_supercell(scaling_matrix[, wrap_coords]) Make supercell.
read_data(*args, **kwargs)
read_dump(*args, **kwargs)
read_xyz(*args, **kwargs)
rotate(**kwargs) Rotate crystal cell lattice, basis, and unit cell.
todict() Return dict of SWNT attributes.
transform_lattice(scaling_matrix[, ...])
translate(t[, fix_anchor_points]) Translate crystal cell basis.