Lifetime of the 197Au Moessbauer γ ray

Recently Potzel and Perlow reported that the linewidth obtained in M\"ossbauer measurements with AuCN and KAu(CN)₂ absorbers is anomalously narrow-only 80% of the value obtained with Au-metal absorbers or expected from the lifetime measurements by delayed coincidence. In an attempt to resolve this discrepancy, the lifetime has been remeasured with the Au source in two different chemical environments. The resulting half-lives were 1.93±0.03 nsec for Au in Pt metal and 1.98±0.06 nsec for Au in solution, in agreement with previous lifetime measurements and recent M\"ossbauer measurements with Au-metal absorbers. The anomaly remains unresolved.