Abstract
The thermal average of the amplitude of a local moment (〈S2〉) in 3d transition metals and alloys is a function of temperature and concentration. It is pointed out that the amplitude 〈S2〉 appears in the second moment of 3s inner-core photoelectron spectra because of the existence of an exchange coupling between 3d electrons and the 3s core hole. This fact provides us with a possible method to measure the amplitude 〈S2〉 by means of inner-core photoelectron spectroscopy.