Atomic ordering in CuGeO3 during the spin-Peierls transition: Calculation of63Cu NQR frequencies

The X_α discrete variation (X_α-DV) method is used to calculate the electronic structures of the clusters modeling the spin-Peierls transition in CuGeO₃. The⁶³Cu NQR frequencies of two centers that fall within the simulated supercell are calculated. It is shown that the nature of the forbidden gap and the⁶³Cu NQR spectral parameters depend on the motion of copper atoms in the chains. Some assumptions are made to explain the fact that dimerization in chains of Cu atoms is experimentally unobservable. Translated from Zhurnal Strukturnoi Khimii, Vol. 38, No. 1, pp. 43–50, January–February, 1997.