Symmetry-adapted linear combination of atomic orbital bases and band-structure computation for quasi-one-dimensional solids

A method to derive LCAO bases adapted to the symmetry of a quasi-one-dimensional crystal is presented. The complete solution is given for chains of L(2q)qmc line-group symmetry in general and for the beryllium hydride polymer and tetracyanoplatinate chain in particular. We also give a quantitative account of computational reductions and discuss band touchings and slopes, crystal-field splitting, and selection rules for direct optical absorption.