Hyperfine Coupling of B-12 in Noble-metals and Al - Enhancement of the Conduction-electron Spin Susceptibility By E-e Exchange

We have remeasured the Korringa contribution T(1e) to the nuclear spin lattice relaxation time of the interstitial B-12 in nobel metals and in Al. The T(1e)T times the squared Knight shift K of B-12 taken from the literature, that is the Korringa product of B-12, shows that the conduction-electron spin susceptibility is exchange enhanced similarly to that sensed by the matrix nucleus. The enhancement factors are equal within the experimental errors for both interstitial and matrix positions in Cu and Ag. The enhancement factors at the boron and at the matrix position are different in Au and Al