The influence of vibrational relaxation on the operation of the 119 μm CH3OH laser

Measurements of the pressure dependence of the relaxation rate of vibrationally excited molecules in the 119 m CH₃OH laser have been correlated with the pressure and pump power dependence of the output power in the framework of a rate-equation model for which numerical and approximate analytical solutions have been obtained. Both diffusion and collisional de-excitation are important, and substantial deviations from thermal equilibrium populations are deduced, consistent with an operating pressure range which increases with pump power.     

Measurement of the relative probability of the decay φ → η′γ in the channel η′ → ηπ0π0, η → γγ

The process e ⁺ e ^? → η′γ, η′ → η π⁰π⁰, η → γγ is investigated by an SND detector in experiment on a VEPP-2M equipment with colliding electron-positron beams. The analysis of experimental data yields a value of B(? → η′γ)=(6.7 _?4.2 ^+5.0 ±1.5)×10^?5 for the decay probability. Taking into account a previous measurement of this quantity by an SND detector in the decay channel η′ → π⁺π^?η, one finally obtains B(?→η ′γ)=(6.7 _?2.4 ^+2.8 ±0.8)×10^?5.     

The influence of quintessence on the motion of a binary system in cosmology

We employ the metric of Schwarzschild space surrounded by quintessential matter to study the trajectories of test masses on the motion of a binary system. The results, which are obtained through the gradually approximate approach, can be used to search for dark energy via the difference of the azimuth angle of the pericenter. The classification of the motion is discussed.     

The Δ mass dependence of the M matrix and its influence on the NΔ→NN cross-sections

TheΔmass dependence of the M matrix and its influence on the NΔ→NN cross-sections are investigated in the one-boson exchange model.Our calculations show that theΔmass dependence of the momentum of the outgoingΔand the M matrix affects the calculations ofσNΔ→NN,especially around the threshold energy.     

The influence of doping on ultimate performance of photodiodes for the 8–14 μm spectral range

The zero-bias resistance-area product (R_oA) of LN₂ temperature Cd_xHg_1−xTe 8–14 μm range photodiodes has been calculated. The influence of the types: the Auger and the radiative recombination in p- and n-type regions was taken into account.It was shown that the photodiode ultimate performance is determined by the Auger 7 recombination in p-type material. The ultimate value of (R_oA) is about 8 Ω cm² and it is much lower than calculated in recent works.     

The CP violation of theB→Kϕ decay at γ(4s) in the non-standard models

The CP violating asymmetry in theB→K? decay is studied in both supersymmetric model and three Higgs doublets model. The absorptive part of the penguin amplitude leads to the CP violating asymmetry in theB _u ^+- →K ^±? decays, which is at most 3% due to the GIM mechanism in the standard model. However, the asymmetry could be relatively large if there exists a new source of the imaginary component in the decay amplitude. In the supersymmetric model, the contributions of the imaginary part of the super-penguin and the super-box processes rather suppress the magnitude of the asymmetry, whereas in the three Higgs doublets model, that of the charged Higgs-penguin process could significantly enhance it.     

The radiative decay ϕ → γππ in a coupled-channel model and the structure of f0(980)

A coupled-channel model is used to study the nature of the scalar mesons produced in the decay ϕ → γππ. The K molecular picture of f₀(980) is found to be in a good agreement with the recent experimental data from SND and CMD-2. The structure of the light scalar mesons is elucidated by investigating the S-matrix poles and the q spectral density.     

The influence of the second harmonic in the current-phase relation on the voltage-current characteristic of high TC DC SQUID

A theory for the voltage-current characteristic in high TC DC SQUIDs (Superconducting Quantum Interference Devices), which accounts for a second harmonic in the junction current-phase relation, is developed. It is shown that the small inductance DC SQUIDs can be used for the investigation of the second harmonic via its influence on the voltage-flux curve. If the second harmonic is perceptible, then for large inductance DC SQUIDs the theory can explain the substantial deviations of the experimental voltage modulation from theoretical predictions and computer simulations based on conventional sinusoidal current-phase relation. The detail comparison with the experiment is performed.     

The influence of temperature on red-edge excitation effects in liquid solutions of N,N′-dimethylaminobenzonitrile

A systematic study of new photophysical and photochemical processes in solutions is continued by the example of a recently found phenomenon of redistribution of the intensities of two fluorescence bands of N,N′-Dimethylaminobenzonitrile (DMABN) in polar solutions at room temperatures under selective irradiation by light with different photon energies in the region of the long-wavelength absorption band. The effects observed are explained using data of quantum-mechanical calculations, which reveal that solutions of these systems are very likely to contain rotational isomers with different orientations of the dimethylamino group with respect to the plane of the benzonitrile residue. The excited-state charge transfer reactions in these rotamers occur in different ways and, hence, with different rates, because of which the intensity ratio of recorded fluorescence bands is different for different wavelengths of selective excitation. In this study, the influence of the temperature on the red-edge excitation effect observed in the fluorescence of DMABN solutions in acetonitrile is studied in the temperature range of 274–313 K using the previously used selective excitation method. It is found that these effects manifest themselves at any temperature within this range, but are especially strong at 313 K. The parameters of the dual fluorescence that are most sensitive for recording of the considered effects are determined, and the obtained temperature dependences are interpreted.     

The influence of microstructure on the martensitic transformation in Cu–Zn–Al melt-spun ribbons

The martensitic transformation was investigated in a set of twin roller melt-spun Cu–Zn–Al shape memory alloys, solidified at tangential wheel speeds between 20 and 40 m/s. The resulting microstructures were analyzed using X-ray diffraction, optical and transmission electron microscopy techniques. The characteristic martensitic transformation temperature, M _S, was determined for each condition by conventional resistometric methods. The ribbons are homogeneous in shape and for each quenching rate they exhibit a quite uniform M _S temperature. By proper thermal treatments, the different factors affecting M _S could be separately examined and from temperature measurements, the contribution of L2₁ antiphase boundaries evaluated. A calculation of this contribution using pair interchange energies is in good agreement with the experimental results.     

The sign of the magnetic moment of191Pt(g.s.) determined by Mössbauer effect on oriented nuclei

Radioactive¹⁹¹Pt(3/2^–) alloyed to iron has been oriented at low temperature in a dilution refrigerator. The resonance absorption spectrum of the 82.4 keV transition of the polarized split source has been registered at high ( 1 K) and low ( 15 mK) temperatures. From the high temperature spectrum (E2/M1; 82.4) < 0 is established. From the positive-to-negative speed asymmetry of the low tempe rature spectrum we determined [191-Pt(g.s.)] > 0. This result is in agreement with deformed Hartree-Fock calculation predictions.     

The decay chain162Yb (19·0 min) →162Tm (21·8 min) →162Er and the decay of160Tm (9·2 min) TO160Er

The decay of¹⁶²Yb,¹⁶²Tm and¹⁶⁰Tm has been investigated with Ge(Li) and Si(Li) detectors using isotopically separated samples produced by the YASNAPP facility at Dubna. The singles -ray spectrum, - and - coincidences were measured. Strong ytterbium and thulium activities were used for conversion electron measurements with high resolution magnetic -spectrographs. 3, 134 and 39 new -rays were attributed to the decays of¹⁶²Yb,¹⁶²Tm and¹⁶⁰Tm, respectively. Decay schemes of these isotopes are proposed. Three and 12 new levels were found in¹⁶²Er and¹⁶⁰Er, respectively. TheQ-values of¹⁶²Yb,¹⁶²Tm and¹⁶⁰Tm were determined to be 2·2, MeV, 4·6±0·3 MeV and 4·9±0·5 MeV, respectively.On leave from theUniversity Tashkent, USSR.On leave fromZfK Rossendorf/Dresden, DDR.On leave from theNuclear Research Institute, e near Prague, CSSR.On leave from theTechnical University, Dresden, DDR.It is a pleasure to thank Professor V. P.Dhzelepov, Dr. D.Netzband and Dr. L.Funke for their support. The valuable assistance of the synchrocyclotron staff of the JINR Dubna and of the electronics teams of the measuring centre of the LNP JINR is gratefully acknowledged.     

Probabilities of rovibronic transitions in the I 1Π g − , J 1Δ g − →C 1Π ± u systems of bands of the deuterium molecule

Probabilities of spontaneous rovibronic transitions I ¹Π _g ^? , v′ J′, J ¹Δ _g ^? , v′, J′→C ¹Π _u ^± , v″, J″ of the D₂ molecule (for vibrational and rotational quantum numbers v′=v″=0–3 and J′=1–9, J″=J′±1) have been obtained for the first time. They were determined using (1) the previously proposed nonadiabatic model, which takes into account the electron-rotational interaction of the upper levels; (2) the coefficients of expansion of wave functions of perturbed states in the Born-Oppenheimer basis, which were found from the experimental data on rovibronic terms; and (3) semiempirical b initio data on electronic transition dipole moments of the 3dπ¹Π_g→2pπ¹Π_u and 3dπδ¹Δ_g→2pπ¹Π_u transitions. The dependences of the transition probabilities on J′ for the same bands of both hydrogen isotopomers H₂ and D₂ were found to be identical. They represent monotone functions for R and P branches and functions with a maximum (minimum) for Q branches. The ratios of transition probabilities of different isotopomers for different branches of the same systems of bands and for the same branches of different systems of bands were found to be correlated. The semiempirical values obtained in the paper agree with the experimental values within the limits of the errors of their determination. The nonempirical values of transition probabilities agree with the experiment considerably worse.     

The influence of the growth rate on the eutectic spacings,undercoolings and microhardness of directional solidified bismuth–lead eutectic alloy

Bi–Pb alloy at the eutectic composition was unidirectionally solidified upwards with five different growth rates (V = 7.05–113.09 μm/s) at constant temperature gradient (G = 2.18 K/mm) in a Bridgman type directional growth furnace in order to investigate dependency of eutectic spacing (λ), minimum undercooling (ΔT) and microhardness (HV) on the growth rates (V). The values of λ and HV were measured from the quenched samples and the minimum undercooling (ΔT) were determined from the Jackson–Hunt eutectic theory. The dependency of eutectic spacings, microhardness and undercooling on growth rate was investigated. According to these results it has been found that the value of λ decreases with increasing the value of V and that the values of HV and ΔT increase for a constant G. The values of λ²V, λΔT and ΔTV^?0.5 were determined by using the values of λ, ΔT and V. The results obtained in the present work have been compared with those predicted by the Jackson–Hunt eutectic theory and with similar experimental results.