Silver atoms in the structural channels of beryl

A silver atom in synthetic beryl is investigated by the EPR and electron spin echo (ESE) spectroscopy. It is established that silver ions were first introduced into the structural channels of beryl by thermodiffusion at 800υC. The Ag⁺ ions are then converted to the Agυ state by the X-ray irradiation of samples at room temperature. Charge changes in manganese and chromium impurities located at the aluminum positions are observed at the same conditions. Four different Agυ centers with isotropic hyperfine interactions (HFI) with ¹⁰⁷ Ag and ¹⁰⁹ Ag nuclei and hyperfine constants less than those for the free Ag atom are revealed by the EPR method. ESE investigations enable us to confirm the positions of silver atoms that are stable up to 230υC.