sknano.structures.SWNT

class sknano.structures.SWNT(n=10, m=0, nz=1, tube_length=None, Lz=None, fix_Lz=False, **kwargs)

SWNT structure class.

Parameters:

n, m : int

Chiral indices defining 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 along the \(z\) dimension

element1, element2 : {str, int}, optional

Element symbol or atomic number of basis Atom 1 and 2

bond : float, optional

Distance between nearest neighbor atoms (i.e., bond length). Must be in units of Å. Default value is the carbon-carbon bond length in graphite, approximately \(\mathrm{a}_{\mathrm{CC}} = 1.42\) Å

Lz : float, optional

Length of the nanotube in nanometers. Overrides the \(n_z\) cell values.

New in version 0.2.5.

tube_length : float, optional

Length of nanotube in units of nanometers. Overrides 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.

Examples

>>> from sknano.structures import SWNT

Create a SWNT with \(\mathbf{C}_{h} = (10, 10)\) 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 \(\mathbf{C}_{h} = (20, 10)\).

>>> 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 \(\mathbf{C}_{h} = (20, 0)\).

>>> 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

Attributes

Ch	SWNT circumference \(|\mathbf{C}_h|\) in Å
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.
bond	Bond length in Å.
chiral_angle	Chiral angle \(\theta_c\) in degrees.
chiral_type
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	Element symbol of Atom 1.
element2	Element symbol of Atom 2.
fix_Lz
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.
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_mass	Unit cell mass in atomic mass units.
unit_cell_symmetry_params

Methods

todict()

Return dict of SWNT attributes.