The Distribution of Cu(II) on Boehmite and Silica Surfaces: Correlating EPR Signal Loss with the Effective Bohr Magneton Number of Sorbed Ions

Abstract The effective Bohr magneton number μ eff of Cu(II) adsorbed at the boehmite/water interface is 14% to 21% less than anticipated for a uniform dispersal of Cu(II) ions throughout the interface. Insufficient evidence for exchange coupling indicates the lost electron paramagnetic resonance signal intensity must largely result from spin–spin relaxation. Polynuclear Cu(II) clusters at the silica/water interface are superparamagnetic with a blocking temperature between 5 K and 7 K. Superparamagnetic Cu(II) clusters at the silica/water interface do not saturate at magnetic fields as high as 10,000 G.