6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

This Account reviews our main achievements in the field of excited-state properties of fullerene derivatives. The photosensitizing and electron-acceptor features of some relevant classes of functionalized fullerene materials are highlighted, considering the impact of functionalization on fullerene characteristics. In addition, the unique optimization in terms of redox potentials, water-solubility, and singlet oxygen generation is presented for several novel fullerene-based materials.

Excited-state properties of C(60) fullerene derivatives.

The pgopher program is a general purpose program for simulating and fitting molecular spectra, particularly the rotational structure. The current version can handle linear molecules, symmetric tops and asymmetric tops and many possible transitions, both allowed and forbidden, including multiphoton and Raman spectra in addition to the common electric dipole absorptions. Many different interactions can be included in the calculation, including those arising from electron and nuclear spin, and external electric and magnetic fields. Multiple states and interactions between them can also be accounted for, limited only by available memory. Fitting of experimental data can be to line positions (in many common formats), intensities or band contours and the parameters determined can be level populations as well as rotational constants. pgopher is provided with a powerful and flexible graphical user interface to simplify many of the tasks required in simulating, understanding and fitting molecular spectra, including Fortrat diagrams and energy level plots in addition to overlaying experimental and simulated spectra. The program is open source, and can be compiled with open source tools. This paper provides a formal description of the operation of version 9.1.

/pdf/pgopher-a-program-for-simulating-rotational-vibrational-and-hhurs09rhf.pdf

PGOPHER: A program for simulating rotational, vibrational and electronic spectra

Fullerenes are graphitic cage structures incorporating exactly twelve pentagons. The smallest possible fullerene is thus C20, which consists solely of pentagons. But the extreme curvature and reactivity of this structure have led to doubts about its existence and stability. Although theoretical calculations have identified, besides this cage, a bowl and a monocyclic ring isomer as low-energy members of the C20 cluster family, only ring isomers of C20 have been observed so far. Here we show that the cage-structured fullerene C20 can be produced from its perhydrogenated form (dodecahedrane C20H20) by replacing the hydrogen atoms with relatively weakly bound bromine atoms, followed by gas-phase debromination. For comparison we have also produced the bowl isomer of C20 using the same procedure. We characterize the generated C20 clusters using mass-selective anion photoelectron spectroscopy; the observed electron affinities and vibrational structures of these two C20 isomers differ significantly from each other, as well as from those of the known monocyclic isomer. We expect that these unique C20 species will serve as a benchmark test for further theoretical studies.

Gas-phase production and photoelectron spectroscopy of the smallest fullerene, C20

Encapsulating atoms or molecules inside fullerene cages could give rise to a myriad of novel molecules and materials. The existence of such species is now strongly supported by a growing body of experimental evidence. Fullerene& ndash;metal complexes generally thought to be endohedral are being produced and purified in milligram quantities, and their structure and properties are beginning to be explored

Atoms in carbon cages: the structure and properties of endohedral fullerenes

Electronic spectra of ion radicals and their molecular orbital interpretation. III. Aromatic hydrocarbons

FULLERENES with metals encapsulated within the carbon cage have been prepared recently1–6. Laser vaporization of a lanthanum-impregnated graphite rod yielded an air-stable, solvent-extractable species comprising a single La atom inside a C82 cage1, denoted La@ C82; a cluster containing two La atoms (La2@ C82) was later reported3. Similar techniques applied to graphite/yttrium rods have produced Y@ C82 and Y2@ C82 (refs 5, 6). Here we describe the preparation of scandium-containing C82 species, including an encapsulated scandium trimer, Sc3@C82. Mass spectrometry and ESR spectroscopy provide evidence that the Sc3, trimer is indeed trapped within the cage.

Encapsulation of a scandium trimer in C 82

Electronic absorption spectra of the radical anions and cations of fullerenes: C60 and C70

ESR and optical studies of the radical anion of C60

Cation radicals of some aromatic hydrocarbons, aliphatic amines, and aromatic amines are produced by ..gamma.. irradiation of frozen glassy solutions using organic halides as the solvent. The electronic absorption spectra of the cation radicals are compared with the photoelectron spectra of the parent molecules in order to find correlations between the two spectra. Complementary aspects of the two types of spectroscopy are discussed.

Tadamasa Shida

Papers

Electronic spectra of ion radicals and their molecular orbital interpretation. III. Aromatic hydrocarbons

Encapsulation of a scandium trimer in C 82

Electronic absorption spectra of the radical anions and cations of fullerenes: C60 and C70

ESR and optical studies of the radical anion of C60

Electronic absorption spectra of some cation radicals as compared with ultraviolet photoelectron spectra