Erratum: Resonant microwave fields and negative magnetic response, induced by displacement currents in dielectric rings: theory and the first experiments.

A correction to this article has been published and is linked from the HTML version of this paper. The error has not been fixed in the paper.

Resonant microwave fields and negative magnetic response, induced by displacement currents in dielectric rings: theory and the first experiments.

The theoretical basis and experimental verification of resonant phenomena in the electromagnetic fields generated by displacement current in the near zone of dielectric ring is presented. According to the traditional viewpoint, the dielectric has an influence on the electric field inside resonator. To the contrary, we demonstrate that the dielectric ring exhibits magnetic properties at resonance. The sliding incidence of plane microwave on this weakly absorbing ring is shown to provide the sharp and deep resonance in the components of generated field; this low loss circuit is operating as a resonant dielectric magnetic dipole. Splitting and broadening of resonance in the pair of these dipoles dependent upon their mutual arrangement is recorded. The phase shift equal to π between the magnetic components of incident and generated wave indicating the formation of negative magnetic response is demonstrated. Perspectives of using of this simple sub wavelength resonant magnetic dipoles in the all-dielectric circuitry are discussed.

Superluminal tunneling of microwaves in smoothly varying transmission lines.

Tunneling of microwaves through a smooth barrier in a transmission line is considered. In contrast to standard wave barriers, we study the case where the dielectric permittivity is positive, and the barrier is caused by the inhomogeneous dielectric profile. It is found that reflectionless, superluminal tunneling can take place for waves with a finite spectral width. The consequences of these findings are discussed, and an experimental setup testing our predictions is proposed.

Polarization-dependent tunneling of light in gradient optics.

Reflection-refraction properties of photonic barriers, formed by dielectric gradient nanofilms, for inclined incidence of both S - and P -polarized electromagnetic waves are examined by means of exactly solvable models. We present generalized Fresnel formulas, describing the influence of the nonlocal dispersion on the reflectance and transmittance of single- and double-layer gradient photonic barriers for S and P waves and arbitrary angles of incidence. The nonlocal dispersion of such layers, arising due to a concave spatial profile of dielectric susceptibility across the plane film, is shown to result in a peculiar heterogeneity-induced optical anisotropy, providing the propagation of S (P) waves in tunneling (traveling) regimes. The results obtained indicate the possibility of narrow-band nonattenuated tunneling (complete transmittance) of oblique S waves through such heterogeneous barriers, and the existence of spectral areas characterized by the strong reflection of P waves and profound contrast between transmitted S and P waves. The scalability of obtained exact analytical solutions of Maxwell equations into the different spectral ranges is discussed and the application potential of these phenomena for miniaturized polarizers and filters is demonstrated.

Is there a minimum size for aqueous doubly charged metal cations?

A major feature of the chemistry of multiply charged solvated metal ions is dissociative charge transfer. It happens because the second ionization potential (IP) of a metal atom usually exceeds the first IP of a solvent molecule. This raises the issue of whether there is a minimum number of ligands below which the species would charge-separate spontaneously. To elucidate this, doubly charged aqueous cations of most common divalent metals (group 2 elements Mn, Fe, Co, Ni, Zn, Cd, and Cu) have been generated using electrospray and examined by collision-induced dissociation in a triple-quadrupole mass spectrometer. We have clearly observed the monoaqua complexes for all aforementioned doubly charged metal ions, except Be for which the smallest complex found is the dihydrate. We have also systematically revisited the matter of critical size--the maximum number of ligands at which dissociative charge transfer is competitive with simple ligand loss.

Prediction of peptide ion mobilities via a priori calculations from intrinsic size parameters of amino acid residues.

Ion mobility spectrometry (IMS) has recently been established as a powerful tool to separate the protease digest mixtures and identify their peptide components. As accurate calculation of mobilities is critical for this technique, a new rapid method based on intrinsic size parameters (ISPs) of amino acid residues has been devised. However, those parameters had to be obtained by tedious statistical analysis of a large body of experimental data. Here we demonstrate that they can instead be derived a priori, based on the stoichiometry of a residue. Our main finding is that the ISP of a residue is essentially determined by its density, that is, the average mass/size ratio of its constituent atoms. This is in accordance with an interpretation in which peptides assume compact conformations in the gas phase dominated by the solvation of ionic charge.

Single-parent evolution algorithm and the optimization of Si clusters.

We describe a novel method for the structural optimization of molecular systems. Similar to genetic algorithms (GA), our approach involves an evolving population in which new members are formed by cutting and pasting operations on existing members. Unlike previous GA's, however, the population in each generation has a single parent only. This scheme has been used to optimize Si clusters with 13-23 atoms. We have found a number of new isomers that are lower in energy than any previously reported and have properties in much better agreement with experimental data.

Broadband antireflection properties of thin heterogeneous dielectric films.

New exactly solvable flexible models of inhomogeneous thin film with smooth and deep variations of dielectric susceptibility epsilon(z) are presented. Formation of cutoff frequencies of such films (as well as the broadband antireflection), controlled by the profiles epsilon(z), is shown. The crucial role of gradients of epsilon(z) in the optics of strongly inhomogeneous media is emphasized.