Experimental evidence for endohedral complexes

The conclusions of the original experiment in which the Ceo La species were first observed [2] have proven less definitive than was hoped. The line of reasoning that led to the belief that the observed molecules were endohedral complexes was questioned by Cox and coworkers [13], who in a subsequent paper [14] concluded that the available experimental evidence did not prove conclusively that the lanthanum atom was indeed trapped inside the Ceo cage. This ambiguity has now been resolved thanks to a whole spectrum of experiments that provided further circumstantial evidence for the endohedral complexes [15], generated externally bound (exohedral) complexes and contrasted their properties with those of endohedral complexes [16], and generated and characterized endohedral complexes [17-21]. 

The unexpected and unprecedented results aforementioned experiment were both confirmed [19,20] 

That the endohedral complexes are produced in both laser 

Properties of the Ceo Cluster Relevant to Formation of Endohedral Complexes 

With gram quantities of fullerenes readily available thanks to the Kratschmer-Huffman arc vaporization technique, several properties of the Ceo cluster have been measured lately. Other data has been provided by recent ab initio calculations. In this section, we list the properties that are of relevance to the formation of endohedral complexes. These include molecular geometry (the bond lengths and the cage radius), ionization potential and electron affinity, and electric polarizability. The so-called endohedral effect is also discussed here. 

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