Influence of Z-pinch evolution on laser pulse duration at 46.9 nm in Ne-like Ar ions

A capillary discharge 46.9 nm Ne-like Ar laser is achieved with peak current of 20–23 kA. The variation of laser pulse duration with initial Ar pressure and rise-time of main current is reported. Measurements show that the laser pulse durations slightly increase with the increased pressure and increased rise-time of current. A comparison of the experimental results with the calculation of snow-plow model indicates that the increase of laser pulse duration is the result of decreased Z-pinch velocity at the pinch time when the radius of plasma is minimal.     

The Effect of the Relative Motion of Atoms on the Frequency of the Emitted Light and the Reinterpretation of the Ives-Stilwell Experiment

We examine the process of the emission of light from an atom that is in a relative translational motion with respect to the medium at rest in which the electromagnetic excitations propagate. The effect of Lorentz contraction of the of electron orbits on the emitted frequency is incorporated in the Rydberg formula, as well as the emitter’s Doppler effect is acknowledged. The result is that the frequency of the emitted light is modified by a factor that is identical with what is called the ‘relativistic Doppler effect’. The new emission formula is applied for reinterpretation of the Ives-Stilwell experiment and shown that within the second order of approximation with respect to the speeds of the atom and the ‘absolute speed’ (Earth’s speed relative to the medium), the absolute motion does not affect the interference. The expression for the modification of the frequency involves both a first and a second-order term with respect to the speed of the atoms in the cathode tube. The latter turns out to be quantitatively the same as if the time would have changed its rate in the frame moving with the atoms. Thus, a new interpretation of the results of this famous experiment is provided without stipulating time dilation.     

Laser induced incandescence determination of the ratio of the soot absorption functions at 532 nm and 1064 nm in the nucleation zone of a low pressure premixed sooting flame

In this work, the two-excitation wavelength laser induced incandescence (LII) method has been applied in a low-pressure premixed methane/oxygen/nitrogen flame (equivalence ratio 2.32) to determine the variation of the ratio of the soot absorption functions at 532 nm and 1064 nm E(m,532 nm)/E(m,1064 nm) along the flame. This method relies on the comparison of LII signals measured upon two different excitation wavelengths (here 532 nm and 1064 nm) and with laser fluences selected in such a way that the soot particles are equally laser-heated. The comparison of the laser fluences at 532 nm and 1064 nm leads to an easy determination of E(m,532 nm)/E(m,1064 nm). The reliability of the method is demonstrated for the first time in a low pressure flame in which the soot nucleation zone can be spatially resolved and which contains soot particles acting differently with the laser fluence according to their residence time in the flame. The method is then applied to determine the profile of E(m,532 nm)/E(m,1064 nm) along the flame. A very important decrease of this ratio is observed in the region of nascent soot, while the ratio remains constant at high distance above the burner. Implication on temperature determination from spectrally resolved measurement of flame emission is studied.     

Analysis of the Opacity of Magnesium XII 0.842 nm Doublet in the Solar Coronal X-ray Spectrum

Using the observed intensity ratio of the magnesium XII 0.842 nm doublet in the solar coronal X-ray spectrum, we investigate the opacity of the (1/2–3/2) component of the magnesium XII doublet. The escape factor and the opacity of the (1/2–3/2) component of the magnesium XII 0.842 nm doublet are discussed. Results show that the opacity has great effect on the (1/2–3/2) component of the magnesium XII 0.842 nm doublet. While using the abundance of magnesium and the results of ionization balance, we calculate the variation of electron density as a function of observed intensity ratio.     

Profile of the ν1 Raman Band of Pure CD4 and Its Mixtures with Ar and Kr in the Gas Phase

The ν₁ band profile of isotropic Raman spectrum of pure CD₄ and its mixtures with Ar and Kr is recorded in the temperature range 140–360 K at pressure of pure CD₄ ranging from 4 to 20 atm and at total pressure of gas mixtures in the interval 4–160 atm. The dependences of the band shape on temperature and density are analyzed. The coefficients of the CD₄ band broadening by Ar and Kr are determined, and the decisive role of vibrational contributions, in particular of the intramolecular energy transfer, is pointed out.     

Inclusive production of protons, anti-protons and neutrons in p+p collisions at 158 GeV/c beam momentum

New data on the production of protons, anti-protons and neutrons in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The charged baryons are identified by energy loss measurement in a large TPC tracking system. Neutrons are detected in a forward hadronic calorimeter. Inclusive invariant cross sections are obtained in intervals from 0 to 1.9 GeV/c (0 to 1.5 GeV/c) in transverse momentum and from ?0.05 to 0.95 (?0.05 to 0.4) in Feynman x for protons (anti-protons), respectively. p _T integrated neutron cross sections are given in the interval from 0.1 to 0.9 in Feynman x. The data are compared to a wide sample of existing results in the SPS and ISR energy ranges as well as to proton and neutron measurements from HERA and RHIC.     

The excitation functions of 4s–4p and 3d–4p transitions in Ni atoms sputtered from metallic targets by Ar+ ions

The intensities of spectral lines corresponding to 4s–4p and 3d–4p transitions in Ni atoms sputtered from metallic targets by Ar⁺ ions were measured. The energy of primary ions was varied from 4 KeV to 10 keV. Both single crystal and polycrystalline targets were used at various temperatures including ferromagnetic and paramagnetic phases. The excitation functions calculated from experimental data can be explained only by the assumption that the promotion of the electrons occurs during energetic binary collisions of atomic particles in the solid.     

The Effect of Disorder on the Free-Energy for the Random Walk Pinning Model: Smoothing of the Phase Transition and Low Temperature Asymptotics

We consider the continuous time version of the Random Walk Pinning Model (RWPM), studied in (Berger and Toninelli (Electron. J. Probab., to appear) and Birkner and Sun (Ann. Inst. Henri Poincaré Probab. Stat. 46:414–441, 2010; ). Given a fixed realization of a random walk Y on ℤ ^d with jump rate ρ (that plays the role of the random medium), we modify the law of a random walk X on ℤ ^d with jump rate 1 by reweighting the paths, giving an energy reward proportional to the intersection time L_t(X,Y)=ò₀^t 1_Xs=Ys dsL_{t}(X,Y)=\int_{0}^{t} \mathbf {1}_{X_{s}=Y_{s}}\,\mathrm {d}s: the weight of the path under the new measure is exp (βL _t (X,Y)), β∈ℝ. As β increases, the system exhibits a delocalization/localization transition: there is a critical value β _c , such that if β>β _c the two walks stick together for almost-all Y realizations. A natural question is that of disorder relevance, that is whether the quenched and annealed systems have the same behavior. In this paper we investigate how the disorder modifies the shape of the free energy curve: (1) We prove that, in dimension d≥3, the presence of disorder makes the phase transition at least of second order. This, in dimension d≥4, contrasts with the fact that the phase transition of the annealed system is of first order. (2) In any dimension, we prove that disorder modifies the low temperature asymptotic of the free energy.     

Study of the High-Resolution Fourier Spectrum of the ν9 and ν2 + ν7 + ν8 Bands of the С2D4 Molecule

Russian Physics Journal - Fourier spectra of the C2D4 molecule in the region 2250–3040 cm–1, in which the fundamental ν9 band and the combinational ν2 + ν7 + ν8 band...     

Inclusive production of charged kaons in p+p collisions at 158 GeV/c beam momentum and a new evaluation of the energy dependence of kaon production up to collider energies

New data on the production of charged kaons in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The kaons are identified by energy loss in a large TPC tracking system. Inclusive invariant cross sections are obtained in intervals from 0 to 1.7 GeV/c in transverse momentum and from 0 to 0.5 in Feynman x. Using these data as a reference, a new evaluation of the energy dependence of kaon production, including neutral kaons, is conducted over a range from 3 GeV to $\mathrm{p}+\overline{\mathrm{p}}$ collider energies.     

Squarks and gluinos at a TeV e + e − collider: testing the identity of Yukawa and gauge couplings in SUSY-QCD

Supersymmetry predicts the identity of Yukawa and gauge couplings in the QCD sector: . We examine whether the  Yukawa coupling can be determined, by methods complementary to LHC, by analyzing squark–gluino final states at a TeV e ⁺ e ⁻ collider.     

Local Fields Without Restrictions on the Spectrum of 4-Momentum Operator and Relativistic Lindblad Equation

Quantum theory of Lorentz invariant local scalar fields without restrictions on 4-momentum spectrum is considered. The mass spectrum may be both discrete and continues and the square of mass as well as the energy may be positive or negative. One may assume the existence of such fields only if they interact with ordinary fields very weakly. Generalization of Kallen-Lehmann representation for propagators of these fields is found. The considered generalized fields may violate CPT-invariance. Restrictions on mass-spectrum of CPT-violating fields are found. Local fields that annihilate vacuum state and violate CPT-invariance are constructed in this scope. Correct local relativistic generalization of Lindblad equation for density matrix is written for such fields. This generalization is particularly needed to describe the evolution of quantum system and measurement process in a unique way. Difficulties arising when the field annihilating the vacuum interacts with ordinary fields are discussed.     

Photolysis of NO2 at multiple wavelengths in the spectral region 200–205 nm

A study of the photodissociation dynamics of NO₂ in the 200–205 nm region using resonance enhanced multiphoton ionization (REMPI) in conjunction with the velocity map imaging technique is presented. We chose this region because it allowed the use of a single laser to photodissociate the NO₂ molecule and probe both the O(¹D₂) fragment using (2+1) REMPI via the 3p'¹P₁ state at 2 ×205.47 nm and the 3p'¹F₃ state at 2 ×203.5 nm, and the O(³P_J) fragments using (2+1) REMPI via the P_J states around 2 ×∼200 nm. Translational energy and angular distributions are extracted from the O(¹D) and O(³P) product images. A growth in the population of highly excited vibrational levels of the NO X(²Π) co-fragment is found as the dissociation wavelength decreases. These are compared with similar trends observed previously for other triatomic O-atom containing molecules. Detailed information on the electronic angular momentum alignment of the ¹D₂ state is obtained from analysis of the polarization sensitivity of the O(¹D) images using the two resonant intermediate states. The angular dependence of the potential energy in the exit channels is examined using long-range quadrupole-dipole and quadrupole-quadrupole interaction terms, from which molecular-frame multipole moments of the total angular momentum of the recoiling O atoms have been calculated. Comparison with the experimentally derived multipole moments is used to help provide insight into the dissociation mechanism.     

Mechanisms of the Insulator—Metal Transition and Spin Crossover in CoO at High Pressure

JETP Letters - The effect of high pressure on the electronic characteristics of CoO is analyzed in the framework of the multielectron model of transition metal oxides. The specific features of spin...     

Design and optimization of thin film polarizer at the wavelength of 1540 nm using differential evolution algorithm

In this paper, a thin film polarizer at the wavelength of 1540 nm in infrared region was designed and optimized using differential evolution method. It is shown how the algorithm’s parameters can change the output result to obtain the best consequence of optimization. This polarizer consists of a few pairs of high and low refractive index dielectric materials, titanium dioxide and silicon dioxide, respectively, with \(BK_{7}\) glass substrate and the angle of incident light was supposed 56° that is the Brewster angle for \(BK_{7}\) glass. Our final optimized polarizer has 91.20 and 0.336% transmittance for P and S polarization, respectively, and a 271 ratio of \(\frac{{T_{P} }}{{T_{S} }}\) which has high significance for this polarizer. It consists of eight pairs of layers with low and high refractive index materials and 3369.1 nm physical thickness which is used to separate S and P polarized light for Q-switching process.