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# sknano.structures.compute_Natoms_per_unit_cell¶

sknano.structures.compute_Natoms_per_unit_cell(*Ch)[source][source]

Compute $$N_{\mathrm{atoms/cell}} = 2N$$.

$N_{\mathrm{atoms}} = 2N = \frac{4(n^2 + m^2 + nm)}{d_R}$

where $$N$$ is the number of graphene hexagons mapped to the nanotube unit cell.

Parameters: *Ch : {tuple or ints} Either a 2-tuple of ints or 2 integers giving the chiral indices of the nanotube chiral vector $$\mathbf{C}_h = n\mathbf{a}_1 + m\mathbf{a}_2 = (n, m)$$. 2N : int Number of atoms in nanotube unit cell: N_{mathrm{atoms}} = 2N = frac{4(n^2 + m^2 + nm)}{d_R}