Enum Bravais

Enum Documentation

enum brille::Bravais

A Bravais letter indicating a centering of a lattice whose conventional cell is centred.

When the unit cell does not reflec the symmetry of the lattice, it is usual to refer to a ‘conventional’ crystallographic basis, (aₛ bₛ cₛ), instead of a primitive basis, (aₚ bₚ cₚ). Such a conventional basis has “extra” lattice points added at the centre of the unit cell, the centre of a face, or the centre of three faces. The “extra” nodes in the conventional basis are displaced from the origin of the unit cell by ‘centring vectors’. As with any space-spanning basis, any whole-number linear combination of the conventional basis vectors is a lattice point but in addition there exist linear combinations xaₛ+ybₛ+zcₛ with at least two fractional coefficients (x,y,z) that are lattice points as well.

Each conventional basis is ascribed a Bravais letter, which forms part of the Hermann-Mauguin symbol of a space group. A subset of the 10 possible Bravais letters is used herein:

For further details, see http://reference.iucr.org/dictionary/Centred_lattice

Values:

enumerator _
enumerator P
enumerator A
enumerator B
enumerator C
enumerator I
enumerator F
enumerator R