Muonium formation

In the case of muonium formation, the integral in Eq. (28.4) can be approximated by an exponential decay of the muonium frequency cog ... 

Attempts to find thermal muonium in vacuum failed An early experiment at the Space Radiation Effects Laboratory (SREL) seemed to show that y" " stopped in thin gold foils emerges as muonium at thermal energies. But more sensitive experiments at LAMPF and SIN observed no muonium formation. 

For the case of muonium, nonresonant spin precession in a magnetic field provides a copious source of information about its crystallographic sites and the associated unpaired electron distribution around them (see Chapter 15). Here, the concentration of muons is always too low for molecule formation, and migration to impurities and implantation defects can be kept small by the short muon lifetime and use of pure material and low temperature. 

Muonium chemistry gaseous phase, 28 119-120 liquid mixtures, 28 120-122 radical formation and reactions, 28 122-130 Mushrooms, vanadium in, 35 96-97 Mutagenesis, site-directed, flavocytochrome bj, 36 289-290 MXj-... 

V W. Hughes, D. W. McColm, K. Ziock, and R. Prepost, Formation of Muonium and Observation of Its Larmor Precession, Physical Review Letters 5, 63-65 (1960). 

The measured amplitudes are usually scaled to give fractional diamagnetic, muonium, and muonic radical polarizations, directly related to the formation probabilities of the species. 

Triaminosilanes have also been prepared from NHC-diaminosilylenes and cyclohexylisocyanide [195]. The reactivity of Af-heterocyclic silylene-NHC complexes with muonium has been explored by Percival et al. According to muon spin spectroscopy and theoretical calculations, radical formation at the exocyclic methylene group or the silicon center is the most likely result [1%]. 

The time window can be extended to even shorter times if there is a muonium precursor state. Evolution of spin polarization in Mu occurs partly at frequencies near the Mu hyperfine frequency (4463 MHz in vacuum, broken arrows in Figure 2), which sets the timescale for loss of phase coherence during formation of the observed muonated species. The formation process can be studied indirectly in transverse fields by interpretation of shifts in the initial phase and concomitant loss of amplitude. Thus, processes occurring on a timescale down to 10 ps can be analysed, but the results rely on the validity of the underlying model. 

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