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:

\[R = (\psi|\tau)\]

*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 . Default value is the carbon-carbon bond length in graphite, approximately \(\mathrm{a}_{\mathrm{CC}} = 1.42\)


(psi, tau) : tuple

2-tuple of floats – \(\psi\) in radians and \(\tau\) in Å.