Muonium states in HgO

Experimental data on muonium states in HgO are presented, Muon spin rotatio n (mu SR) experiments show that, at low temperatures, approximately 80% of muons implanted into a polycrystalline sample form paramagnetic centres wit h hyperfine interaction parameters A(iso) = 14.93(5) MHz and D = 5.2(1) MHz . The remaining 20% form diamagnetic states. Diffusion of the paramagnetic state through equivalent sites is observed above 10 K, averaging the appare nt anisotropy to a low value at and above 50 K. The variations of the ampli tudes of the two signals with temperature indicate that the paramagnetic ce ntres ionize in a temperature range centred around 160 K and that the assoc iated donor levels lie considerably further from the conduction band edge t han the corresponding states in ZnO and other II-VI compounds.