The prior statistics of object colors is of much interest because extensive statistical investigations of reflectance spectra reveal highly non-uniform structure in color space common to several very different databases. This common structure is due to the visual system rather than to the statistics of environmental structure. Analysis involves an investigation of the proper sample space of spe...

A central feature in the Hilbert space formulation of classical mechanics is the quantisation of classical Liouville densities, leading to what may be termed term Groenewold operators. We investigate the spectra of the Groenewold operators that correspond to Gaussian and to certain uniform Liouville densities. We show that when the classical coordinatemomentum uncertainty product falls below He...

We derive detailed theoretical models for 1074 nearby stars from the SPOCS (Spectroscopic Properties of Cool Stars) Catalog. The California and Carnegie Planet Search has obtained high-quality (R ≃ 70000− 90000, S/N ≃ 3− 500) echelle spectra of over 1000 nearby stars taken with the Hamilton spectrograph at Lick Observatory, the HIRES spectrograph at Keck, and UCLES at the Anglo Australian Obser...

The electronic spectra of carbon nanotubes and other nanoscale systems are quantized because of their small radii. Similar quantization in the phonon spectra has been difficult to observe because of the far smaller energy scale. We probed this regime by measuring the temperature-dependent specific heat of purified single-wall nanotubes. The data show direct evidence of one-dimensional quantized...

The exciton scattering (ES) approach attributes excited electronic states in quasi-1D branched polymer molecules to standing waves of quantum quasiparticles (excitons) scattered at the molecular vertices. We extract their dispersion and frequency-dependent scattering matrices at termini, ortho, and meta joints for pi-conjugated phenylacetylene-based molecules from atomistic time-dependent densi...

The calculation of the vibrational structure associated to electronic spectra in large molecules requires a Taylor expansion of the initial and final state potential energy surface (PES) around some reference nuclear structure. Vertical (V) and adiabatic (A) approaches expand the final state PES around the initial-state (V) or final-state (A) equilibrium structure. Simplest models only take int...

Excited-state geometries and electronic spectra of butadiene, acrolein, and glyoxal have been investigated by the symmetry adapted cluster configuration interaction (SAC-CI) method in their s-trans conformation. Valence and Rydberg states below the ionization threshold have been precisely calculated with sufficiently flexible basis sets. Vertical and adiabatic excitation energies were well repr...

Scanning near-field optical spectroscopy was applied to semipolar ð20 2 1Þ InGaN/GaN quantum wells (QWs) to evaluate spatial homogeneity of QW band gap and its dependence on the growth conditions. In the most uniform QW, photoluminescence (PL) spectra were found to be narrow with small peak wavelength and spectral width variations. A QW grown at reduced temperature showed sub-micrometer size PL...

We demonstrate the utility of a two-pulse sequence in obtaining high-resolution solid state NMR spectra of half-integer quadrupolar nuclei with magic-angle-spinning (MAS). The experiment, which utilizes multiple/single-quantum correlation, was first described in a different form by Frydman and Harwood [J. Am. Chem. Soc. 117 (1995) 5367] and yields high-resolution isotropic NMR spectra where shi...