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: Either a 2tuple 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 carboncarbon bond length in graphite, approximately \(\mathrm{a}_{\mathrm{CC}} = 1.42\) Å
Returns: (psi, tau) : tuple
2tuple of floats – \(\psi\) in radians and \(\tau\) in Å.