Optical spectra are presented for a sample of T dwarfs, obtained using the Keck 10m Low Resolution Imaging Spectrograph. Dominant features are discussed, including possible temperature diagnostics. We have used the Low Resolution Imaging Spectrograph (LRIS; Oke et al. 1995), mounted on the Keck 10m Telescope, to obtain red optical spectra of nine T dwarfs selected from Burgasser et al. (1999, 2...

This experiment is an exercise in optical spectroscopy in a study of the spectra of “hydrogenic” atoms, i.e. atoms with one “optical” electron outside a closed shell of other electrons. Measurements include finding: the Balmer lines of atomic hydrogen and the fine structure of sodium lines; determination of the mass of the deuteron from the isotope shift. A high-resolution scanning monochromato...

The quantum mechanical nature of an electron bound to a nucleus is well-shown by the discrete emission lines observed in spectroscopy of hydrogenic atoms. We determine the calibration of the spectroscopic apparatus used by measuring the emission lines of mercury. We then determine the value of the hydrogen Rydberg constant by measuring the Balmer emission lines of hydrogen along with the ratio ...

We present a new method called optical coherence correlation spectroscopy (OCCS) using nanoparticles as reporters of kinetic processes at the single particle level. OCCS is a spectral interferometry based method, thus giving simultaneous access to several sampling volumes along the optical axis. Based on an auto-correlation analysis, we extract the diffusion coefficients and concentrations of n...

This Minireview discusses novel insights into the electronic structure of carbon nanotubes obtained using single-molecule fluorescence spectroscopy. Fluorescence spectra from single nanotubes are well described by a single, Lorentzian lineshape. Nanotubes with identical structures fluoresce with different energies due to local electronic perturbations. Carbon nanotube fluorescence unexpectedly ...

Single phase BiFeO3 (BFO) nanoparticles as a visible light photocatalyst were successfully synthesized by thermal decomposition of the glyoxylate precursor. The glyoxylate precursors were formed by the redox reaction between ethylene glycol and nitrate ions. The phase evolution, structure and optical properties of BFO nanoparticles were characterized by X-ray diffraction, electron microscopy an...

in this research the composition of polyurethane closed cell (pucc) with two different concentrations of sio2 nanoparticles (1.0 and 2.0 wt%) have been prepared. optical microscopy and sem imaging, watering uptake, ftir and raman spectroscopy of the synthesized samples were carried out. the optical microscopy imaging of samples showed differences in the appearance of matrix produced by applying...

We report optical spectroscopic measurements of molecular positronium (Ps(2)), performed via a previously unobserved L=1 excited state. Ps(2) molecules created in a porous silica film, and also in vacuum from an Al(111) crystal, were resonantly excited and then photoionized by pulsed lasers, providing conclusive evidence for the production of this molecular matter-antimatter system and its exci...