Study of Sodium Colloids in Heavily Irradiated NaCl Crystals by Nuclear Magnetic Resonance

Strong irradiation of NaCl crystals results in a formation of sodium colloids which exhibit metallic properties. In consequence, besides the ²³Na line of NaCl a second well-separated ²³Na line occurs in the NMR spectrum caused by the Knight shift of the conduction electrons. We present Knight shift and nuclear spin relaxation measurements performed on the “metallic” ²³Na line in e^–-irradiated NaCl single-crystals between about 4 and 390 K. Evaluation of the data leads to detailed information on the electronic properties, atomic self-diffusion, and melting behavior of the colloids. The results are discussed in view of corresponding data obtained in bulk sodium.