Spectroscopic guest-host effect

Because the size regime of n=l-6 atoms is of great practical significance to the spectroscopic, chemical and catalytic properties of supported metal clusters in both weakly and strongly interacting environments (28), it is important to study very small metal clusters in various types of substrate as well as in the gas phase. In this way, one can hope to develop a scale of metal cluster-support effects (guest-host interactions) and evaluate the role that they play in diverse technological phenomena. 

The origin for the less-than-optimal repeatability of ITC titrations can be traced to systematic errors in sample treatment as well as to difficulties in data evaluation. First in line of the factors that interfere with the reproducibility of calorimetric results is the purity of the compounds used. Owing to the ubiquity of heat effects, even small deviations from a nontinal composition of a compound may result in dramatic differences in the calorimetric output. A frequent problem of this kind in abiotic host-guest binding is the presence of the solvent of crystallization. Ordinarily, this is not considered an impurity, as it is often present in a fixed stoichiometric ratio and can be accounted for in elemental analyses and in the spectroscopic evaluation. In calorimetry, however, solvent of crystallization adds a heat contribution of unknown size, which does not emerge from the interaction under study and thus tends to falsify the results. The problem is amplified by the polarity... 

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