Reactive molecular collision calculations

The chemistry of muonium, a light isotope of hydrogen, is investigated for the time period immediately after stopping of its precursor, the positive muon, in the condensed phase. Information is extracted from the initial amplitudes of the muon precession signals arising from muonium and muon-substituted diamagnetic compounds. In liquid water part of the initial spin polarization cannot be accounted for in terms of existing models of muonium formation and reaction. This missing fraction is postulated to arise via a spin exchange interaction of muonium with a hydrated electron. It is also suggested that the chemical fate of the muon is determined by reactions with transient species created in the terminal spur of the muon track.

Radiolysis effects in muonium chemistry

https://research.kek.jp/people/mibe/g-2/muonium/papers/NIM_surfacemuonbeam.pdf

A high stopping density μ + beam

Muonium-substituted transient radicals observed by muon spin rotation

Production of thermal muonium in the vacuum between the grains of fine silica powders

We report a precise measurement of the rate of reaction of muonium atoms with bromine molecules in an argon moderator gas at a atm and 23 °C. The bimolecular rate constant is k= (2.4±0.3) ×1011 l/mole‐sec, ten times higher than that for the analogous reaction of hydrogen atoms. Since muonium can properly be treated as a light isotope of hydrogen, this comparison has potential significance for the theory of reaction rates. The technique is described and the results discussed.

A. E. Pifer

Papers

Muonium chemistry in gases: Mu+Br2

The chemical reaction of muonium with Cl2 in the gas phase