In muon catalyzed fusion /CF/ in the mixture of deuterium and tritium, there is a small probability of muon sticking on a fusion product4He and this causes a limit of cycle number of CF in the reaction system: D+T
4He+n. The sticking loss is, however, to be re-considered by a bond rupture model of hot atom chemistry because the process has similarity to hot atom chemical phenomena.
Chemical behaviour of a helium muonide atom /He
o/ can be understood on the analogy of its hydrogen homologues, muonium /Mu/, deuterium /Do/ and tritium /To/. In muon catalyzed fusion /CF/, a small fraction of negative muon in the fusion cycle sticks to helium to give proton-like He
+ which easily picks up one electron forming He
o. The energy of He
+ at birth is about 3.5 MeV being in a similar situation to the case of a hot tritium atom produced by /n, p/ or /n, / reaction. The reaction cross section and rate of He
o reactions are estimated.
Possibility of negative muon transfer from helium muonide He
+ to T /or D/ through collisional excitation after muon catalyzed fusion has been pointed out. The transfer process depends on the efficiency of collisional excitation of He
+ in the medium of tritium or deuterium. It is argued that tritium has larger nuclear stopping power and better excitation efficiency than deuterium. This effect is in the same direction as the tritium concentration dependence of muon loss probability in recent experimental work.
Hot atom chemical reaction by50Cr/n, /51Cr and52Cr/, n/51Cr reactions, and recoil implantation reaction by51V/p, n/51Cr reaction were investigated using geometrical isomers /mer and fac/ of tris/benzoylacetonato/ chromium/III/ /Cr/ba/3/. The production of counter isomer was observed for both mer- and fac-targets, although the yield of labelled parent isomer was larger. The observed mer/fac yield ratio suggests that the main formation mechanism of51Cr/ba/3 is the reaction of ba– and Cr/ba/
which has the same geometrical configuration of target complex, and the substitution reaction of central metal atom by recoil51Cr. Furthermore, implantation gave rise to a much higher yield of labelled Cr/ba/3 compared to the case of in situ nuclear recoils.
Recoil implantation of Tc and Ru in metal acetylacetonates were performed using ruthenium metal as a source and MIII/acac/3 and MII/acac/2 complexes as catchers. The recoil atoms were obtained by100Ru/, p/99mTc and98Ru/, n/97Ru reactions. The yields of Tc/acac/3 and Ru/acac/3 were clearly dependent on the force constant of the bond between the central metal atom and oxygen in acetylacetone K/M–O/. A plot of the yield vs. 1/K(M–O) showed a linear relationship. However, the yield of Tc/acac/2 implanted in M/acac/2 did not show such a dependence on the force constant. The difference of the mechanism of complex formation between Tc/acac/3 and Tc/acac/2 was discussed on the basis of a reaction cage surrounding the recoil atom and of reaction time necessary for competition between the recoil atom and the central metal of the catcher complex.