compute_T

sknano.core.structures.compute_T(*Ch, bond=None, length=True, **kwargs)

Compute length of nanotube unit cell \(|\mathbf{T}|\) in Å.

\[|\mathbf{T}| = \frac{\sqrt{3} |\mathbf{C}_{h}|}{d_{R}} = \frac{\sqrt{3}a\sqrt{n^2 + m^2 + nm}}{d_{R}} = \frac{3a_{\mathrm{CC}}\sqrt{n^2 + m^2 + nm}}{d_{R}}\]

Parameters:

• *Ch –

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

• 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
• length (bool, optional) – Compute the magnitude (i.e., length) of the translation vector.

Returns:

If length is True, then return the length of unit cell in Å.

If length is False, return the componets of the translation vector as a 2-tuple of ints (\(t_1\), \(t_2\)).

Return type:

float or 2-tuple of ints