Search results for "pole [approximation]"
showing 10 items of 522 documents
A Theoretical Study of the Electronic Spectra of N9 and N7 Purine Tautomers
1999
The complete active space (CAS) SCF method and multiconfigurational second-order perturbation theory (CASPT2) have been used to study electronic spectra of the N(9)H and N(7)H tautomers of purine. The calculations include vertical excitation energies, oscillator strengths, dipole moments, and transition moment directions in gas phase. In accord with experiment in nonpolar solvents, the two lowest π → π* excited singlet valence states are predicted to be located at 4.7 and 5.1 eV. The latter is expected to shift to the red in aqueous solutions. A satisfactory interpretation of the electronic spectra above 5.5 eV is obtained if the experimental data are assumed to consist of the superposition…
C3v Top Data System (C3vTDS) software for spectrum simulation of XY3Z symmetric-top molecules using the group chain
2010
Abstract The C3v Top Data System (C3vTDS) program suite has been developed with the aim of studying any rovibrational band or polyad of XY3Z (C3v) symmetric-tops molecules in a singlet electronic state. It is developed in the same way as similar programs for various molecular symmetries (Td, Oh, C4v, C2v and D2h). We work in the O ( 3 ) ⊃ C ∞ v ⊃ C 3 v group chain and this choice has consequences on the method used to specify the input parameters for Hamiltonian and transition moment calculations. One example concerning the ν 2 band of the CH 3 12 D symmetric-top molecule is presented. This package consists in a series of FORTRAN programs called by scripts. The whole package is freely acces…
Levels of 137Cs in game and soil in Opole Anomaly, Poland in 2012–2020
2021
Abstract Once deposited, radiocesium remains in the environment for a long time, and constantly enters the food chain. Over time, game species tend to accumulate 137Cs by two orders of magnitude more than farm animals. This occurs especially in places heavily contaminated, thus meat products made out of local game should be treated with caution. One of such areas, known as the Opole Anomaly, is located in South-Western Poland and represents one of most 137Cs contaminated regions across Europe after the Chernobyl accident. The aim of the study was to find out the 137Cs activity in soil and local game, the value of the soil-to-game aggregated transfer factor and to assess the effective dose o…
The behavior of the 180° domain walls in disordered dielectrics like KTaO3 : Li and KTaO3 : Nb
2003
We calculate the structure of 180° domain wall in disordered ferroelectrics with random site electric dipoles (i.e. those like K 1-x Li x TaO 3 , KTa 1-x Nb x O 3 , where Li + or Nb 5+ are off-center ions forming impurity dipoles). The calculation is performed on the base of the free energy functional of disordered dielectrics derived earlier [M. D. Glinchuk et al., Phase Transit., 2003 (to be published)] within the framework of a random field method. We obtain the domain wall thickness as a function of impurity dipole concentration n and temperature T. It is shown that in disordered ferroelectrics the domain wall is usually broader than in their ordered counterparts. The thickness increase…
Resonance Dipole-Dipole Interaction Between Two Accelerated Atoms in the Presence of a Reflecting Plane Boundary
2018
We study the resonant dipole-dipole interaction energy between two uniformly accelerated identical atoms, one excited and the other in the ground state, prepared in a correlated {\em Bell-type} state, and interacting with the scalar field or the electromagnetic field nearby a perfectly reflecting plate. We suppose the two atoms moving with the same uniform acceleration, parallel to the plane boundary, and that their separation is constant during the motion. We separate the contributions of vacuum fluctuations and radiation reaction field to the resonance energy shift of the two-atom system, and show that Unruh thermal fluctuations do not affect the resonance interaction, which is exclusivel…
Surface Lattice Resonances in Self-Assembled Arrays of Monodisperse Ag Cuboctahedra
2019
Plasmonic metal nanoparticles arranged in periodic arrays can generate surface lattice plasmon resonances (SLRs) with high Q-factors. These collective resonances are interesting because the associated electromagnetic field is delocalized throughout the plane of the array, enabling applications such as biosensing and nanolasing. In most cases such periodic nanostructures are created via top-down nanofabrication processes. Here we describe a capillary-force-assisted particle assembly method (CAPA) to assemble monodisperse single-crystal colloidal Ag cuboctahedra into nearly defect-free >1 cm2 hexagonal lattices. These arrays are large enough to be measured with conventional ultraviolet-visibl…
Vacuum fluctuations and radiation reaction contributions to the resonance dipole-dipole interaction between two atoms near a reflecting boundary
2018
We investigate the resonance dipole-dipole interaction energy between two identical atoms, one in the ground state and the other in the excited state, interacting with the electromagnetic field in the presence of a perfectly reflecting plane boundary. The atoms are prepared in a correlated (symmetric or anti-symmetric) Bell-type state. Following a procedure due to Dalibard et. al. [J. Dalibard et. al., J. Phys. (Paris) {\bf 43}, 1617 (1982); {\bf 45}, 637 (1984)], we separate the contributions of vacuum fluctuations and radiation reaction (source) field to the resonance interaction energy between the two atoms, and show that only the source field contributes to the interatomic interaction, …
New constraints on Lorentz invariance violation from the neutron electric dipole moment
2010
We propose an original test of Lorentz invariance in the interaction between a particle spin and an electromagnetic field and report on a first measurement using ultracold neutrons. We used a high sensitivity neutron electric dipole moment (nEDM) spectrometer and searched for a direction dependence of a nEDM signal leading to a modulation of its magnitude at periods of 12 and 24 hours. We constrain such a modulation to $d_{12} < 15 \times 10^{-25} \ e\,{\rm cm}$ and $d_{24} < 10 \times 10^{-25} \ e\,{\rm cm}$ at 95~\% C.L. The result translates into a limit on the energy scale for this type of Lorentz violation effect at the level of ${\cal E}_{LV} > 10^{10}$~GeV.
Analysis of fumonisins B1, B2 and B3 in corn-based baby food by pressurized liquid extraction and liquid chromatography/tandem mass spectrometry
2008
A sensitive and reliable method using pressurized liquid extraction (PLE) and liquid chromatography (LC)/electrospray ionization (ESI) tandem mass spectrometry with a triple quadrupole (QqQ) analyzer has been developed for the analysis of fumonisin B(1) (FB(1)), fumonisin B(2) (FB(2)) and fumonisin B(3) (FB(3)) in corn-based baby foods. Influence of several extraction parameters that affect PLE efficiency such as temperature, pressure, solvent extraction, number of cycles and dispersant/clean-up agents were studied. The selected PLE operating method was: 3g of sample was packed into 11 ml stainless-steel cell and fumonisins were extracted with methanol at 40 degrees C, 34 atm in one cycle o…
A new bi-faced log periodic printed antenna
2005
In this paper, a new design of a broadband planar printed antenna based on the academic log periodic antenna is presented. The antenna consists of a series of printed dipoles, distributed on both faces of the substrate. Some configurations are explored, with a different number of printed dipoles. These are designed, simulated, fabricated, and measured. The calculated and measured return losses and radiation patterns are presented. The utility of the proposed antenna associated with its frequency bandwidth is better than 80%. The measured absolute gain is 6.5 dBi, and the front-to-back ratio is around 8 dB. The presented antenna should find wide applications in wireless communication systems…