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# sknano.structures.compute_symmetry_operation¶

sknano.structures.compute_symmetry_operation(*Ch, *, bond=None)[source][source]

Compute symmetry operation $$(\psi|\tau)$$.

The symmetry vector R represents a symmetry operation of the nanotube which arises as a screw translation–a combination of a rotation $$\psi$$ and translation $$\tau$$. The symmetry operation of the nanotube can be written as:

$R = (\psi|\tau)$
Parameters: *Ch : {tuple or ints} Either a 2-tuple of ints or 2 integers giving the chiral indices of the nanotube chiral vector $$\mathbf{C}_h = n\mathbf{a}_1 + m\mathbf{a}_2 = (n, m)$$. 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 (psi, tau) : tuple 2-tuple of floats – $$\psi$$ in radians and $$\tau$$ in Å.