THEORY OF HYPERFINE INTERACTIONS ASSOCIATED WITH THE NEGATIVE MUON INLANTHANUM COPPER-OXIDE HIGH T-C SYSTEM

We have carried out first-principles Unrestricted Hartree-Fock Cluster investigations to demonstrate that the Auger holes produced by the en try of mu(-) into the oxygen ions in La2CuO4 lead to stable O(-)mu(-) centers at apical and planar sites. The hyperfine fields associated wi th these two sites suggest that the apical one is responsible for the stronger and more anisotropic Knight shift in mu SR measurements and t he planar for the weaker and less anisotropic shift, the needed suscep tibility arising from the localized magnetic moments on the O(-)mu(-) centers. This identification of the susceptibility provides support fo r the model proposed for the observed increase in mu SR relaxation rat e below the superconducting temperatures.