Long-lived clusters

Stillinger (1980) suggested that disconnected icebergs should not be present, but that a more likely model is that of a random, three-dimensional network of hydrogen bonds, rather than long-lived clusters of molecules. Such networks of hydrogen-bonded water molecules and clusters are present when hydrates form or dissociate. These clusters are discussed relative to nucleation of hydrates in the following chapter. 

Long-lived clusters Cu , Ni , Co , Sn , Tl , Pb (Table 4) may be formed in deaerated basic medium, but Zn clusters are oxidized into zinc hydroxide within a few weeks even in the absence of Oj. Clusters Cd are better stabilized by gelatin. Ni or Co clusters display ferromagnetic behaviour. Whereas all of these non-precious metal clusters are easily oxidized in solution by O2, they may be stabilized in air after drying under inert atmosphere. 

The cell fluid (cytoplasm) is also inhomogeneous. Clustering of solutes has been observed even for small molecules such as methanol, and there is increasing evidence that at least some soluble proteins in such concentrated solution form relatively long-lived clusters [20, 21]. 

Linnert T, Mulvaney P, Henglein A, Weller H (1990) Long-lived nonmetallic silver clusters in aqueous-solution - preparation and photolysis. J Am Chem Soc 112 4657-4664... 

These findings, shown in Figure 6-4, that lifetimes for the formation of both unprotonated ammonia clusters and protonated ammonia clusters are very short through the C state can only be explained by the AID mechanism. In considering the ADI mechanism, the neutral species (NH3) H, if present, would be formed by the predissociation of ammonia it would be a long-lived species (microsecond lifetime) (Gellene and Porter 1984). Hence, for the ADI mechanism, the lifetime of the C state would be expected to be equivalent to the lifetime of the intermediate (NH3) H. However, we observe a lifetime of less than 100 fs which could be instrumentally limited. Direct ionization is certainly responsible for the sharp... 

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