# compute_T¶

sknano.core.structures.compute_T(*Ch, bond=None, length=True, **kwargs)[source] [edit on github][source]

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. 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 ($$t_1$$, $$t_2$$). float or 2-tuple of ints