Negative muons were trapped in gaseous mixtures of hydrogen and oxygen
. The time distributions of the muonic oxygen X-rays showed a clear de
viation from a single exponential structure. From these time distribut
ions we evaluated the transfer rate from thermalized muonic hydrogen a
toms to oxygen. In order to test the hypothesis of an energy-dependent
transfer rate to oxygen we performed Monte Carlo simulations of the t
hermalization and the transfer process. We report on the present statu
s of our investigations.