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sknano.structures.compute_symmetry_operation

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

Compute symmetry operation (ψ|τ).

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

R=(ψ|τ)
Parameters:

*Ch : {tuple or ints}

Either a 2-tuple of ints or 2 integers giving the chiral indices of the nanotube chiral vector Ch=na1+ma2=(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 aCC=1.42

Returns:

(psi, tau) : tuple

2-tuple of floats – ψ in radians and τ in Å.