One-Centre Expansion and Structure Constants

A wave function for a MT potential of a non-overlapping array of MT wells, vmt( Ir RI), centre sites R of a three-dimensional periodic lattice and embedded in the same constant potential as in (5.2) may be written as the linear combination of MTO s 

Below we show that as an alternative to the multi-centre expansion (5.28), the wave function may be written in terms of a one-centre expansion of the form 

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