Alkali metals nuclear properties

In this section, we extend the above discussion to the isotopomers of X3 systems, where X stands for an alkali metal atom. For the lowest two electronic states, the permutational properties of the electronic wave functions are similar to those of Lij. Their potential energy surfaces show that the baniers for pseudorotation are very low [80], and we must regard the concerned particles as identical. The Na atom has a nuclear spin " K, and K have nuclear... 

Solutions of alkali metals in liquid ammonia have been studied by many techniques. These include electrical conductivity, magnetic susceptibility, nuclear magnetic resonance (NMR), volume expansion, spectroscopy (visible and infrared), and other techniques. The data obtained indicate that the metals dissolve with ionization and that the metal ion and electron are solvated. Several simultaneous equilibria have been postulated to explain the unique properties of the solutions. These are generally represented as follows ... 

There are two principal synthetic routes to dicarboxylate complexes. One of these uses an aqueous solution of the alkali metal dicarboxylate and the corresponding metal halide,93 while the other depends upon the dicarboxylic acid reduction of higher oxidation state metals. This reductive property of oxalic acid results in its ready dissolution of iron oxides and hence a cleaning utility in nuclear power plants.94 Mention must also be made of the successful ligand exchange synthesis of molybdenum dicarboxylates, Mo(dicarboxylate)2 H2 O, from the corresponding acetate complex. Unfortunately the polymeric, amorphous and insoluble nature of these complexes has restricted the study of these systems, which may well provide examples of multiple M—M bonding in dicarboxylate coordination chemistry.95... 

Whereas some interesting 15N-FTNMR complexation studies have been carried out by Roberts (52), more promising results have been obtained from alkali metal NMR (53-57). The nuclear and spectral properties of the alkali and alkaline earth elements are shown in Table... 

All the M2+ ions are smaller and considerably less polarizable than the iso-electronic M+ ions, as the higher effective nuclear charge binds the remaining electrons tightly. Thus the effect of polarization of cations on the properties of their salts are less important. Ca, Sr, Ba, and Ra form a closely allied series in which the properties of the elements and their compounds vary systematically with increasing size in much the same manner as in the alkali metals. 

When such clusters are formed in beams, essentially by many slow collisions of alkali atoms within a nozzle, it is found experimentally (by analysing the mass distribution using a time of flight spectrometer) that there are discontinuities in the intensity distribution of the peaks from which abundances can be computed for each cluster size. These discontinuities correspond to enhanced stability of metallic clusters around specific sizes (8, 20, 40, 58, etc). They are the same for all the different alkali metals, and are therefore referred to as magic numbers see fig. 12.5. They also turn out to be the same (at least, for the first few magic numbers) as those observed in nuclear physics. This similarity has led to an explanation based on the shell model and to the suggestion that the jellium model can be used to account for the properties of metallic clusters [683]. 

---