Comparative Spectroscopic Characterization of the Basic and the Higher Fullerenes

Recent Advances in IR and UV/VIS Spectroscopic Characterization of the C76 and C84 Isomers of D2 Symmetry

“…450 to 1650 cm −1 . The general pattern of the obtained spectra and all the observed absorption bands of the chromatographically isolated samples of the stable C 76 and C 84 isomers with D 2 symmetry from the several different original, advanced separation processes [22][23][24][25][26][27][28] are in excellent agreement with the semiempirical, ab initio, and density functional theory (DFT) theoretical calculations for these molecules [5-12, 29, 30] over the mentioned relevant region. It should be noted that some low frequencies can exist below the observational limit of 400 cm −1 .…”

Photochemical Transformation of Fullerenes

“…Eklund and co-workers in a pioneering study on the photoinduced dimerization of C 60 fullerene thin fi lms. [ 31 , 32 ] The generic reaction scheme preceding fullerene dimerization is presented in Figure 2 a, where k 1 -k 6 represents the rate constants of the possible reaction paths between the ground-state monomer, M, the singlet-excited monomer, 1 M * , the triplet-excited monomer, 3 M * , and the dimer, D. Note that monomers in the higher excited singlet states are omitted from the diagram, as they decay very rapidly down to the fi rst excited singlet state; [33][34][35] this rationalizes why the symbol 1 M * is used collectively for the end state of the fi rst excitation step. The division into a k 5 and k' 5 path describes two alternative reaction paths to the D state, and will be discussed in detail later.…”

“…Within the limits of accuracy of the experimental data presented in Figure 1 c, we fi nd that the fi lm can be fully dimerized, and also Eklund et al interpreted their experimental Raman spectroscopy data as though the overall M → D reaction-rate constant was limited by, and proportional to, the incident light intensity, and therefore suggested that only a single photon is required to be absorbed in order for a dimer to form. [ 32 , 36 ] Notably, all backreaction paths, i.e., k 2 , k 4 and k 6 , must in such a scenario be effectively zero. As a unity absorbed-photon-to-dimer yield is in obvious contradiction to our fi nding of an intensity-dependent dimerization effi ciency (see Figure 1 c and accompanying discussion), we set out to analyze our data in more detail; specifi cally, we are interested in calculating our attained absorbedphoton-to-dimer effi ciency.…”

“…[ 1 , 2 ] This novel group of nanomaterials exhibit a wide range of exotic and appealing properties, which render them interesting study objects for fundamental investigations [3][4][5][6][7][8][9] as well as exploitable as active materials in a plethora of ubiquitous applications, notably photovoltaic devices, [10][11][12][13][14][15][16][17] transistor arrays, [18][19][20] and integrated circuits. [ 1 , 2 ] This novel group of nanomaterials exhibit a wide range of exotic and appealing properties, which render them interesting study objects for fundamental investigations [3][4][5][6][7][8][9] as well as exploitable as active materials in a plethora of ubiquitous applications, notably photovoltaic devices, [10][11][12][13][14][15][16][17] transistor arrays, [18][19][20] and integrated circuits.…”

“…Fullerenes are nanometer-sized spherical-shaped molecules, comprising a shell of carbon atoms intra-molecularly bonded via a combination of single and double bonds. [ 1 , 2 ] This novel group of nanomaterials exhibit a wide range of exotic and appealing properties, which render them interesting study objects for fundamental investigations [3][4][5][6][7][8][9] as well as exploitable as active materials in a plethora of ubiquitous applications, notably photovoltaic devices, [10][11][12][13][14][15][16][17] transistor arrays, [18][19][20] and integrated circuits. [21][22][23][24] One interesting property of fullerene molecules (monomers) is that they can be transformed into dimeric or polymeric structures under illumination by UV and visible light, where the chemical coupling between different fullerene monomers is effectuated by a photo-induced break-up of intra-molecular double bonds.…”