Wavefunction character of the F-center in table salt

The wave character of an F-type color center in sodium chloride has been investigated using ab initio band structure calculations in the super-cell approach. Although the F-center, consisting of a zero-charge nucleus and an electron, can be regarded as the most delocalized 'atom', calculations show a localized character of its 1s state. The influence of the F-center extends over 12 angstrom. The wave character of the defect band originates mainly from the chlorine 4s states rather than the sodium 3s states, in line with the available experimental results.