Resonances and pseudoresonances in a potential with attractive coulomb tail: A study using analytic‐continuation techniques

The performance of the complex absorbing potential (CAP) and the complex scaling (CS) methods in the detection and calculation of complex Siegert energies is studied using a 1‐D long‐range attractive model potential. This potential is constructed to mimic molecular properties, in particular an attractive Coulombic term, to allow one to draw conclusions on molecular ab initio studies. Analyzing the spectrum of the model potential, one compact bound state embedded in the manifold of Rydberg states is found that shows artificial resonance characteristics when applying the CAP and the CS methods. This pseudoresonance problem is less pronounced in the calculation using the CS method than in that using the CAP method. Despite this deficiency, the CAP method is shown to possess advantages over CS when dealing with physical resonances under conditions that simulate the application of standard basis sets in ab initio calculations. The accuracy of the Siegert energy is shown to be maintained when applying a subspace projection technique to the CAP method. This technique reduces the computational demand significantly and leads to an important improvement of the CAP method, which should be of particular significance in molecular applications. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003     

Temperature compensation of dye doped polymeric microscale lasers

In this article, a new technique for building temperature compensated microscale lasers that are based on the morphology dependent resonances phenomenon is presented. The dome shaped resonator is made with a mixture of NBA 107 UV curable polymer and rhodamine 6 g dissolved in ethanol solution. Since polymers usually exhibit linear thermal expansion and thermo‐optic coefficients that are opposite in sign but similar in order of magnitude, it is possible to compensate for temperature over the dome shaped resonator by tuning the dye concentration and the ratio between the polymer and dye solution. Experiments with dye concentration between 10^?2 to 10^?3 M and polymer and dye solution ratios between 1:1 and 4:1 are conducted. The sensitivity for all cases is presented, and the quality factor Q is investigated. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 789–792     

Influence of damping on the excitation of the double giant resonance

We study the effect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. Taking Pb+Pb collisions as example, we study the resulting effect on the excitation amplitudes, and cross sections as a function of the width of the states and of the bombarding energy. Received: 13 July 1999     

On degenerate resonances and “vortex pairs”

Hamiltonian systems with 3/2 degrees of freedom close to non-linear autonomous are studied. For unperturbed equations with a nonlinearity in the form of a polynomial of the fourth or fifth degree, their coefficients are specified for which the period on closed phase curves is not a monotone function of the energy and has extreme values of the maximal order. When the perturbation is periodic in time, this non-monotonicity leads to the existence of degenerate resonances. The numerical study of the Poincaré map was carried out and bifurcations related to the formation of the vortex pairs within the resonance zones were found. For systems of a general form at arbitrarily small perturbations the absence of vortex pairs is proved. An explanation of the appearance of these structures for the Poincaré map is presented.      

Recent results on nucleon resonance electrocouplings from the studies of π~+π~-p electroproduction with the CLAS detector

Recent results on nucleon resonance studies in π~+π~-p electro- production off protons with the CLAS detector are presented. The analysis of CLAS data allowed us to determine all essential contributing mechanisms, providing a credible separation between resonant and non-resonant parts of the cross sections in a wide kinematical area of invariant masses of the final hadronic system 1.3 < W < 1.8 GeV and photon virtualities 0.2 < Q~2 < 1.5 GeV~2. Electrocouplings of several excited proton states with masses less than 1.8 GeV were obtained for the first time from the analysis of π~+π~-p exclusive electroproduction channel.     

Suppressing the effect of disorders using time-reversal symmetry breaking in magneto-optical photonic crystals: An illustration with a four-port circulator

In integrated optical systems, nonreciprocal elements are indispensable devices that eliminate multi-path reflection between components. To miniaturizing these devices down to a single-wavelength scale, we study nonreciprocal effects in point defects of magneto-optical photonic crystals. The nonreciprocal effect splits degenerate mode pairs and its strength is maximized by spatially matching the magnetic domain pattern with a modal cross product. The resultant eigenmodes are a pair of counter-rotating states that lack time-reversal symmetry. Based upon these eigenmodes, we propose a micro-cavity four-port circulator constructed by coupling a magneto-optical cavity with two waveguides, where each rotating state supports light tunneling along a different direction. In the presence of strong magneto-optical couplings, due to time-reversal symmetry breaking, the performance of the isolator is fundamentally protected from the effect of small structural fluctuations. Numerical calculations demonstrate a four-port circulator with a 26 dB isolation and a roughness tolerance on the order of 0.1a, where a is the lattice constant of the crystal.     

Boron-, Sulfur- and Nitrogen-Doped Polycyclic Aromatic Hydrocarbon Multiple Resonance Emitters for Narrow-Band Blue Emission

Two boron-, sulfur- and nitrogen-doped polycyclic aromatic hydrocarbon multiple resonance thermally activated delayed fluorescence emitters with high photoluminescent quantum efficiency (88 %) and rapid reverse intersystem crossing (k_RISC= 1.0×10⁵ s⁻¹) are designed and synthesized, enabling efficient narrow-band blue electroluminescence at 473 nm with full width at half maximum of 29 nm and maximum external quantum efficiency of 22.0 %, which provides an avenue to expand the structure library for multiple resonance emitters and an approach to regulate their emission properties.     

Far-infrared giant dipole resonances in neutral quantum dots

A resonance behaviour of the far-infrared absorption probability at a frequency N^1/4 is predicted for clusters of N electron–hole pairs (2N110) confined in disk-shaped quantum dots. For radially symmetric dots, the absorption is dominated by a giant dipole resonance, which accounts for more than 98% of the energy-weighted photoabsorption sum rule.