P

Pah (see Space groups) PAH (see Polyaromatic hydrocarbons) Palladium CM-Pd complex, 322, 896 Parity (see also Group theory), 90, 178, 340, 346, 354, 357, 359, 361, 415, 430, 469, 470, 474, 475, 478, 487, 504, 647 Passivation, 281, 888-891 Patents, 870, 908-910 Patterning, 213, 881, 888-890, 893, 894 Pauli paramagnetism, 569, 584, 667, 739, 744-746, 748, 750, 825 Cs concentration dependence, 745, 746 many-body corrections, 584 Pauli principle, 91, 92, 343, 430, 431, 472 Pauli-allowed states, 95,...

Info

Notation temperature-programmed desorption (TPD), molecular beam spectroscopy (MB), Auger electron spectroscopy (AES), and scanning tunneling microscopy (STM). b Dissolution of C60 into surface of the aluminum foil occurred. Therefore no desorption could be observed. c Reaction of C l0 with the surface occurred to form carbide. Therefore no desorption was observed. Notation temperature-programmed desorption (TPD), molecular beam spectroscopy (MB), Auger electron spectroscopy (AES), and scanning...

Classification and Structure of Doped Fullerenes

Fullerene solids are unique insofar as they can be doped in several different ways, including endohedral doping (where the dopant is inside the fullerene shell), substitutional doping (where the dopant is included in the fullerene shell), and the most commonly practiced exohedral doping (where the dopant is outside or between fullerene shells). Doped fullerenes in the crystalline phase are often called fullerides, in contrast to the term fullerite, which refers to the crystalline phase prior to...

Fullerene Chemistry and Electrochemistry

Fullerene chemistry has become a very active research field, largely because of the uniqueness of the C60 molecule 10.1 and the variety of fullerene derivatives that appear to be possible. The synthesis of crystalline M3C60 (M K, Rb, Cs) compounds by the chemical reduction of C60 with alkali metals led to the discovery in 1991 of moderately high temperature (Tc 20 K) superconductivity in these compounds 10.2 . Since that date, chemists have learned how to generate a diverse group of fullerene...

Synthesis Extraction and Purification of Fullerenes

Fullerene molecules are formed in the laboratory from carbon-rich vapors which can be obtained in a variety of ways, e.g., resistive heating of carbon rods in a vacuum, ac or dc plasma discharge between carbon electrodes in He gas, laser ablation of carbon electrodes in He gas, and oxidative combustion of benzene argon gas mixtures. Most methods for the production of large quantities of fullerenes simultaneously generate a mixture of stable fullerenes (C60, C70, ), impurity molecules such as...

1

5.1, 5.2, 5.3, 9.1, 9.2), and techniques for the endohedral doping of fullerenes are reviewed in 5.4. 9.3.1. Charge Transfer Compounds Based on Alkali Metals and Alkaline Earths One general approach to alkali metal (M) doping is to introduce a near-stoichiometric amount of M to oxygen-free C60 films, single crystals, or microcrystalline powder placed in a sealed glass tube. The tube is then evacuated and raised in temperature to 200-300 C to promote intercalation. Depending on the grain size...

Carbon Materials

In this chapter the structure and properties of the various forms of carbon, carbon clusters, and molecules are reviewed. The concepts of sp2 and sp3 bonding and the carbon phase diagram are introduced. It is further noted that many of the known forms of carbon, which have been studied and characterized on the size scale of 1 u.m and higher, have analogs on the nanometer scale in the various types of fullerene and fullerene-related structures that are described in this volume. Carbon-based...

ImUa13

Where sQ is the permittivity of free space, w is the frequency the incident of light, n is the index of refraction, and c is the speed of light, estimates for Im Stj) can be made, yielding the values given in Table 13.10 13.195,203 . The results show that the imaginary part of Xmcxx exceeds the corresponding real part. In view of the uncertainties about values for xfxxx, this conclusion requires further confirmation. The origin of the optical nonlinearity is probably connected with the high...

C

Fig. 3.2. (a) Top view and (b) side view of the nonplanar corannulene molecule, (c) A pyraclene or pyracylene molecule. The pyracylene and corannulene motifs are seen on the surface of C60 and other fullerenes. particular interest in showing the separation between nearest pentagons. Adherence to the isolated pentagon rule, whereby the distance between pentagons on the fullerene shell is maximized, reduces local curvature and stress and gives added stability to C60 3.6,7 , as discussed below....

Vibrational Modes

In this chapter we review the lattice mode structure for the isolated fullerene molecules and for the corresponding molecular solid. Explicit results are given for C60, C70, and higher fullerenes. The effects of doping, photopolymerization, and pressure on the vibrational spectra are reviewed. 11.1. Overview of Mode Classifications Because solid C60 is very nearly an ideal molecular solid, its vibrational modes can be subdivided naturally into two classes intermolecular vibrations (or lattice...

Fullerene Purification Sublimation

Working Soxhlet Apparatus Animation

See Eq. (5.1) for the definition of S. Unless noted otherwise, the data refer to values at 295 K 5.30 . ''These data refer to values at 303 K 5.29 , powder is heated above the sublimation temperature of C60. At T 400 C, the sublimation rate for C60 in vacuum is favored by a factor of 20 over that of C70 5.26 , Therefore, since C70 is normally a factor of 7 less abundant in arc soot than C60, a reasonably pure molecular beam of C60 can be obtained. For example, if a Knudsen cell 5.28 containing...

Kjf

G-factor, 670, 674-676, 680, 743, 753, 836, 838 anisotropy, 675, 676, 753, 836, 838 g-value, 670, 673-678, 680-682, 750, 753, 836, 838 carbon nanotubes, 836, 838 GaAs substrate (see Substrates) GaSe substrate (see Substrates) GeS substrate (see Substrates) Gas phase purification (see Purification) Geodesic dome, 7, 8 Geological connections (see also Fulgurite, Shungite), 1, 9-11, 110 Glass transition (see also Magnetic properties, spin glass), 192, 878 Glassy carbon (see Carbon materials) Grain...

Linear Polymer Chain Containing 250monomeric

Here X and Y refer to different monomers. Block copolymers consist of interconnected homopolymer chains, such as (-X4Y3-)n shown in Fig. 10.24. Graft copolymers, on the other hand, often exhibit homopolymer side chains. The proclivity for C60 to form free radicals and react with various reagents, as already described throughout this chapter, indicates that the incorporation of C60 into a polymer structure should be possible. This incorporation might be accomplished in one of...

Omo

However, as also pointed out in 7.1.2, the point group Tk has no fourfold axes, so that there are two ways to align the twofold axes of the C60 anions, and these two orientations are shown more explicitly in Fig. 8.8. Keeping the same orientation for the z-axis, we see that the x- and _y-axes can have two different orientations either (a) or (b, c) as shown in Fig. 8.8, where (b, c) are equivalent. To arrive at orientation (b, c) from orientation (a) in Fig. 8.8, we can rotate the...

E EEtk

Assuming a parabolic dispersion relation for the three bands, and t,( ) oc EPi, then the diffusion thermopower can be written as where Et refers to the ith band at the Fermi level and r, crja 14.177 . For impurity scattering r, 1 3, pi -1 2 and 1 EF (1 3) l ,. Using a 3D free electron model for the carriers, Eq. (14.21) becomes which is linear in 7. Furthermore, the phonon drag term 5p(7) is proportional to 74 since where the specific heat term C(q) oc T3 (since the phonon density of states at...

Ko

The graphene layer separation is generally larger). A similar charge transfer process is observed for alkali metals and alkaline earths, which dope fullerenes and transfer electrons forming fullerene anions. Also, the distances of the dopants to the nearest-neighbor carbon atoms are similar for doped fullerenes and for GICs. However, the conduction process in doped fullerenes is very different from that in GICs because of differences in electronic bandwidths and the dimensionality of the...

A

Fig. 15.1. (a) Early reports on the dependence of Tc for various M,M'3_ xCm compounds on the fee lattice constant a0 15.16 . (b) More complete summary of the dependence of Tc on aa 15.12 , including points provided by pressure-dependent studies of Tc 15.17 , to the intermolecular degrees of freedom, while the pairing is generally believed to be dominated by high-frequency intramolecular vibrations, although the detailed pairing mechanism still remains an open question at this time (see 15.7)....

Us 5350569 Us 5341639 Us 4922827 Us 5288342 Us 5234475 Jp 5124894

US United States patent JP Japanese FR French DE German WO International patent application EP European patent application. ing blocks for new chemicals will be a very important future application. Rechargeable batteries may turn out to be another promising application, due to the fact that reversible attachment of hydrogen to C60 could provide a charge storage per unit mass that is better than current metal hydride battery technology 20.150 . Somewhat similar considerations apply to hydrogen...

S

Room temperature drain current e vs. drain-source voltage VDS characteristics at various gate voltages VG 0, 30, 40, 50, 60 V for a fullerene-derived field effect transistor with conduction in an -type C60 C70 channel induced at the SiO2-C l0 interface 20.49 , A schematic diagram for the device is shown in Fig. 20.8 b . that the fullerene transistors are -channel devices, consistent with C60 anion formation. Field effect mobilities of up to 0.08 cm2 V s were obtained from the ID-VDS...