More concerning CDW phasing in 2H-TaSe2

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Abstract
The material covered in an earlier paper is re-examined in the light of the analysis of the electron microscope intensity data by Bird and co-workers (1985) that a new type of delta delta structure forms the ground state in 2H-TaSe2. By examining the characteristics of the most stable alpha alpha , beta beta , gamma gamma and delta delta structures, guidelines are established on the electronic factors enhancing the stability of a particular choice of phasing. In particular, attention is drawn to the symmetry breaking, a delta delta structure implies at the single-sandwich level, and the effect this will have on the important Gamma K saddle points in the band structure. With regard to the discommensuration arrays above lock-in the structure delta delta 3(+) has the unique characteristic of forming 1/2a0 discommensurations with itself rotated through 120 degrees . This minimises the drive to DC partialisation through alpha alpha 3(+). Further refined band-structural work is now required to see why delta delta 3(+), not delta delta 3(-), is the ground state in 2H-TaSe2. Perhaps it is at this level that finally disproportionation and cation cluster formation play a role.