compute_symmetry_operation¶

sknano.core.structures.
compute_symmetry_operation
(*Ch, bond=None)[source] [edit on github][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 –
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) – 2tuple of floats – \(\psi\) in radians and \(\tau\) in Å.
Return type:  *Ch –