Electronic structures fluorinated fullerenes

Since the knowledge of electronic structure is essential to the understanding of the chemical/electrochemical and physical behaviors of fullerenes and to their electrochemical applications, the electronic structures of molecular and solid C60, and the changes in electronic structure upon fluorination are discussed extensively in this review. Emphasis is also placed on the selective syntheses of fluorinated fullerenes which are necessarily related to their molecular structures. The molecular structures have been essentially determined by NMR determination of the molecu-... 

An attractive feature of fullerenes is the interaction of their n electrons with fluorine, which has given a very broad array of fullerene fluorides as is described in the previous section. Electronic properties of these new fluorides based on the third allotrope of carbon are of great interest and importance from the view points of materials science and potential use. In fact, as will be described in the next section, electrochemical properties such as electromotive force and reduction potential strongly reflect the changes in the C6o electronic structure through fluorination. 

Fluorinated fullerenes have drawn much attention because of their potential uses such as cathode material for a high energy density cell, electric devices, etc., and there have been several reports on the electrochemical behavior of fluorofullerenes C60FA and C7oFY. Electrochemical studies on these materials provide another way to understand the changes in electronic structures upon fluorination. 

The a values of fullerenes increase as the degree of fluorination increases and, consequently, the electronic structures of fluorinated fullerenes varies as a function of the number of fluorine atoms attached to the fullerene molecules. These results... 

Basic investigations such as selective syntheses, structural and electronic properties of fluorinated fullerenes have recently been much developed as was discussed earlier in this chapter. In general, however, research on applications is still at a very early stage. Potential applications of these materials would be related to their characteristic physical and chemical properties, some of which are summarized in Table 3. 

Carbon atoms crystallize in several forms. Graphite and diamond are well known carbon polymorphs. Fullerenes, which were discovered in the 1980 s, have also been well characterized. Carbon materials show a variety of different physical and chemical properties. Because of this the electronic structure of carbon materials has been investigated using a number of different experimental techniques, for example, XPS, UPS and XANES. Theoretical studies of carbon materials have been also performed. However, experimentally observed spectra are not always consistent with theoretical predictions. Recently, in order to understand the various kinds of observed electronic spectra, DV-Xa calculations have been performed on a small cluster model. [1] In the present paper, we report results of DV-Xa calculations performed on the carbon materials graphite, alkali graphite intercalation compounds (GIC), fullerene, and fluorinated fullerenes. 

We previously reported the results of DV-Xa calculations on Cgo, CeoFae and C6oF48- [2] In that paper, we compared calculated DOS results with the observed spectra of fluorinated fullerenes with varying numbers of fluorine atoms. However, recently, new methods for the synthesization of high purity fluorinated fullerenes have been discovered. [3, 4, 5, 6] Since this discovery, a lot of spectra related to the electronic structure of pure fluorinated fullerenes have become available. In the present paper, we compare calculated DOS of these materials with the observed spectra. Furthermore, we also perform DV-Xq calculations on CeoFig, a material which was discovered only recently. [7]... 

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