Fano Resonances in Mid-Infrared Spectra of Single-Walled Carbon Nanotubes

This work revisits the physics giving rise to the carbon nanotubes phonon bands in the mid- infrared. Our measurements of doped and undoped samples of single-walled carbon nanotubes in Fourier transform infrared spectroscopy show that the phonon bands exhibit an asymmetric lineshape and that their effective cross-section is enhanced upon doping. We relate these observations to electron-phonon coupling or, more specifically, to a Fano resonance phenomenon. We note that only the dopant-induced intraband continuum couples to the phonon modes and that defects induced in the sidewall increase the resonance probabilities.Comment: 5 pages, 4 figures and 1 Supplementary Information File (in pdf

Probing the Birth and Ultrafast Dynamics of Hydrated Electrons at the Gold/Liquid Water Interface via an Optoelectronic Approach

The hydrated electron has fundamental and practical significance in radiation and radical chemistry, catalysis and radiobiology. While its bulk properties have been extensively studied, its behavior at buried solid/liquid interfaces is still unclear due to the lack of effective tools to characterize this short-lived species in between two condensed matter layers. In this study, we develop a novel optoelectronic technique for the characterization of the birth and structural evolution of solvated electrons at the metal/liquid interface with a femtosecond time resolution. We thus recorded for the first time their transient spectra (in a photon energy range from 0.31 to 1.85 eV) in situ with a time resolution of 50 fs. The transient species show state-dependent optical transition behaviors from being isotropic in the hot state to perpendicular to the surface in the trapped and solvated states. The technique will enable a better understanding of hot electron-driven reactions at electrochemical interfaces

Why do employees speak up? Examining the roles of LMX, perceived risk and perceived leader power in predicting voice behavior

Purpose The purpose of this paper is to understand better why employees voice. Drawing on social information processing theory and insights derived from the literature on power, the authors suggest that leader–member exchange (LMX) fosters voice by reducing the perceived risk of voicing. The authors further contend that high perceived leader power will strengthen this mediated relationship. Design/methodology/approach The authors relied on a sample of 265 employee-supervisor dyads collected from Chinese organizations to test the study hypotheses. Findings Results indicated that perceived risk of voicing significantly mediated the positive LMX–voice behavior relationship. In addition, perceived leader power strengthened the effect of LMX on voice behavior via perceived risk of voicing. The relationship of LMX to perceived risk of voicing was more negative, and the indirect effect of LMX on voice behavior was more positive when employees perceived that leader power was high. Practical implications Organizations seeking to promote voice behaviors should support leaders to develop high-quality relationships with employees. Organizations should also ensure that leaders are sufficiently empowered to fulfill their roles, and ensure that employees are aware of their leaders’ influence. Originality/value Findings suggest that, in the context of high quality leader–member relationships, employees’ perceptions of their leaders’ power may help to overcome barriers associated with speaking up. Thus, this study helps explain the conditions that encourage employees to voice

Rodrigues Formula for the Nonsymmetric Multivariable Hermite Polynomial

Applying a method developed by Takamura and Takano for the nonsymmetric Jack polynomial, we present the Rodrigues formula for the nonsymmetric multivariable Hermite polynomial.Comment: 5 pages, LaTe

Braid Structure and Raising-Lowering Operator Formalism in Sutherland Model

We algebraically construct the Fock space of the Sutherland model in terms of the eigenstates of the pseudomomenta as basis vectors. For this purpose, we derive the raising and lowering operators which increase and decrease eigenvalues of pseudomomenta. The operators exchanging eigenvalues of two pseudomomenta have been known. All the eigenstates are systematically produced by starting from the ground state and multiplying these operators to it.Comment: 11 pages, Latex, no figure

Theory of electronic transport through a triple quantum dot in the presence of magnetic field

Theory of electronic transport through a triangular triple quantum dot subject to a perpendicular magnetic field is developed using a tight binding model. We show that magnetic field allows to engineer degeneracies in the triple quantum dot energy spectrum. The degeneracies lead to zero electronic transmission and sharp dips in the current whenever a pair of degenerate states lies between the chemical potential of the two leads. These dips can occur with a periodicity of one flux quantum if only two levels contribute to the current or with half flux quantum if the three levels of the triple dot contribute. The effect of strong bias voltage and different lead-to-dot connections on Aharonov-Bohm oscillations in the conductance is also discussed

Equivalence of the super Lax and local Dunkl operators for Calogero-like models

Following Shastry and Sutherland I construct the super Lax operators for the Calogero model in the oscillator potential. These operators can be used for the derivation of the eigenfunctions and integrals of motion of the Calogero model and its supersymmetric version. They allow to infer several relations involving the Lax matrices for this model in a fast way. It is shown that the super Lax operators for the Calogero and Sutherland models can be expressed in terms of the supercharges and so called local Dunkl operators constructed in our recent paper with M. Ioffe. Several important relations involving Lax matrices and Hamiltonians of the Calogero and Sutherland models are easily derived from the properties of Dunkl operators.Comment: 25 pages, Latex, no figures. Accepted for publication in: Jounal of Physics A: Mathematical and Genera

The monomeric glutamyl-tRNA synthetase of Escherichia coli. Purification and relation between its structural and catalytic properties.

The glutamyl-tRNA synthetase has been purified to homogeneity from Escherichia coli with a yield of about 50%. It is a monomer with a molecular weight of 56,000 and has the same kinetic properties as those of the alpha chain of the dimeric alphabeta-glutamyl-tRNA synthetase described previously (Lapointe, J., and Söll, D. (1972) J. Biol. Chem. 247, 4966-4974). It is the smallest amino-acyl-tRNA synthetase purified from E. coli and contains no important sequence repetition. It is also the only monomeric aminoacyl-tRNA synthetase reported so far to contain no major sequence duplication. Considering its structural and mechanistic similarities with the glutaminyl- and the arginyl-tRNA synthetases of E. coli, we propose the existence of a relation between the true monomeric character of the glutamyl-tRNA synthetase (as opposed to monomers with sequence duplications) and its requirement for tRNA in the activation of glutamate. A single sulfhydryl group of the native enzyme reacts with 5,5'-dithiobis(2-nitrobenzoic acid) causing no loss of enzymatic activity, whereas four such groups per enzyme react in the presence of 4 M guanidine HCl.journal article1979 Jan 25importe