THE synthesis of molecular carbon structures in the form of C60 and other fullerenes1 has stimulated intense interest in the structures accessible to graphitic carbon sheets. Here I report the preparation of a new type of finite carbon structure consisting of needle-like tubes. Produced using an arc-discharge evaporation method similar to that used for fullerene synthesis, the needles grow at the negative end of the electrode used for the arc discharge. Electron microscopy reveals that each needle comprises coaxial tubes of graphitic sheets, ranging in number from 2 up to about 50. On each tube the carbon-atom hexagons are arranged in a helical fashion about the needle axis. The helical pitch varies from needle to needle and from tube to tube within a single needle. It appears that this helical structure may aid the growth process. The formation of these needles, ranging from a few to a few tens of nanometres in diameter, suggests that engineering of carbon structures should be possible on scales considerably greater than those relevant to the fullerenes. On 7 November 1991, Sumio Iijima announced in Nature the preparation of nanometre-size, needle-like tubes of carbon — now familiar as 'nanotubes'. Used in microelectronic circuitry and microscopy, and as a tool to test quantum mechanics and model biological systems, nanotubes seem to have unlimited potential.

Helical microtubules of graphitic carbon

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangula...

/pdf/the-optical-properties-of-metal-nanoparticles-the-influence-16vrpkvhkg.pdf

The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment

The emerging field of plasmonics has yielded methods for guiding and localizing light at the nanoscale, well below the scale of the wavelength of light in free space. Now plasmonics researchers are turning their attention to photovoltaics, where design approaches based on plasmonics can be used to improve absorption in photovoltaic devices, permitting a considerable reduction in the physical thickness of solar photovoltaic absorber layers, and yielding new options for solar-cell design. In this review, we survey recent advances at the intersection of plasmonics and photovoltaics and offer an outlook on the future of solar cells based on these principles.

Plasmonics for improved photovoltaic devices

This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

/pdf/the-hitran-2008-molecular-spectroscopic-database-1ud8clpej3.pdf

The HITRAN 2008 molecular spectroscopic database

BASIC THEORY. Electromagnetic Theory. Absorption and Scattering by an Arbitrary Particle. Absorption and Scattering by a Sphere. Particles Small Compared with the Wavelength. Rayleigh--Gans Theory. Geometrical Optics. A Potpourri of Particles. OPTICAL PROPERTIES OF BULK MATTER. Classical Theories of Optical Constants. Measured Optical Properties. OPTICAL PROPERTIES OF PARTICLES. Extinction. Surface Modes in Small Particles. Angular Dependence of Scattering. A Miscellany of Applications. Appendices. References. Index.

/pdf/absorption-and-scattering-of-light-by-small-particles-49q04h3v4l.pdf

Absorption and Scattering of Light by Small Particles

A new form of pure, solid carbon has been synthesized consisting of a somewhat disordered hexagonal close packing of soccer-ball-shaped C60 molecules. Infrared spectra and X-ray diffraction studies of the molecular packing confirm that the molecules have the anticipated 'fullerene' structure. Mass spectroscopy shows that the C70 molecule is present at levels of a few per cent. The solid-state and molecular properties of C60 and its possible role in interstellar space can now be studied in detail.

Solid C60: a new form of carbon

A new magnetic material with appreciable optical transmission in the visible region at room temperature has been isolated as a gamma-Fe(2)O(3)/polymer nanocomposite. The synthesis is carried out in an ion-exchange resin at 60 degrees C. Magnetization and susceptibility data demonstrate loading-dependent saturation moments as high as 46 electromagnetic units per gram and superparamagnetism for lower loadings where particle sizes are less than 100 angstroms. Optical absorption studies show that the small-particle form of gamma-Fe(2)O(3) is considerably more transparent to visible light than the single-crystal form. The difference in absorption ranges from nearly an order of magnitude in the "red" spectral region to a factor of 3 at 5400 angstroms. The magnetization of the nanocomposite is greater by more than an order of magnitude than those of the strongest room-temperature transparent magnets, FeBO(3) and FeF(3).

https://science.sciencemag.org/content/sci/257/5067/219.full.pdf

Matrix-Mediated Synthesis of Nanocrystalline γ-Fe2O3: A New Optically Transparent Magnetic Material

The infrared and ultraviolet absorption spectra of laboratory-produced carbon dust: evidence for the presence of the C60 molecule

The authors report on the further physical and chemical characterization of the new forms of molecular carbon, C{sub 60} and C{sub 70}. Results demonstrate a high yield of production (14%) under optimized conditions and reveal only C{sub 60} and C{sub 70} in measurable quantity, in an 85:15 ratio. These two new molecular forms of carbon can be completely separated in analytical amounts by column chromatography on alumina. Comparison among mass spectra obtained by the electron impact, laser desorption, and fast atom bombardment (FAB) methods allows a clear assessment of the composition of the mixed and pure samples, and of the fragmentation and double ionization patterns of the molecules. In addition, spectroscopic analyses are reported for the crude mixture by {sup 13}C NMR and by IR spectroscopy in KBr pellet, and for pure C{sub 60} and C{sub 70} in solution by UV-vis spectroscopy.

Donald R. Huffman

Papers

Absorption and Scattering of Light by Small Particles

Solid C60: a new form of carbon

Matrix-Mediated Synthesis of Nanocrystalline γ-Fe2O3: A New Optically Transparent Magnetic Material

The infrared and ultraviolet absorption spectra of laboratory-produced carbon dust: evidence for the presence of the C60 molecule

Characterization of the soluble all-carbon molecules C60 and C70