共查询到20条相似文献,搜索用时 46 毫秒
1.
M. E. Akopyan I. Yu. Novikova S. A. Poretsky A. M. Pravilov A. G. Smolin T. V. Fedorova 《Optics and Spectroscopy》2005,99(1):36-42
The emission spectra caused by the transitions from the ion-pair states and f0 g + and G1g of the I2 molecule are obtained by excitation of individual rovibronic levels of the molecule by the method of optical-optical double resonance. The emission spectra from the state F0 u + populated due to collisions I2(f) + I2(X) are also measured. By modeling the experimental emission spectra, the dipole moment functions for the electronic transitions f g + -B0 u + , A0 u + , and B″0 u + ; G1g-A0 u + and B″0 u + ; and F0 u + -X0 g + and a′0 g + of the iodine molecule are reconstructed. 相似文献
2.
N. Kh. Dzhemilev S. F. Kovalenko S. E. Maksimov O. F. Tukfatullin Sh. T. Khozhiev 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2017,11(3):490-495
The dependences of the emission and fragmentation of clusters sputtered by Xe+ ions from the surface of Si n O m + on the oxygen pressure near the bombarded surface are studied using secondary ion mass spectrometry. It is shown that the process of Si n O m + cluster formation under ion bombardment can be described within the framework of the mechanism of combinatorial synthesis by taking into account the mutual reversibility of the reactions of formation and unimolecular decay. 相似文献
3.
S. N. Morozov U. Kh. Rasulev 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(2):105-108
Secondary-ion mass spectra and energy distributions upon bombarding a gallium arsenide single crystal using Bim+(m = 1–5) cluster ions with energies of 2–12 keV are investigated. The gallium cluster ion yield grew nonadditively with the number of atoms in the cluster projectiles. A quasi-thermal component found in the energy spectra of secondary Ga+ and Ga2+ ions is indicative of the occurrence of the thermal spike mode upon cluster ion bombardment. The quasi-thermal component in the yield of atomic Ga+ ions upon bombardment with Bi2+–Bi5+–ions is 35–75%. 相似文献
4.
T. K. Rebane 《Physics of Atomic Nuclei》2009,72(1):55-58
The stability of m 1 + m 2 + m 3 ? m 4 ? Coulomb systems formed by particles of unit charge against dissociation is considered as a function of the particle mass. It is shown that, from the stability of the m 1 + m 2 + m 3 ? three-particle system, it follows that the m 1 + m 2 + m 3 ? m 4 ? four-particle system containing an additional particle of mass satisfying the condition m 4 ? ? m 3 ? is stable. The results of calculations of the stability domain for m 1 + m 2 + m 3 ? systems asymmetric in particle masses are reported. The stability of 39 asymmetric exotic four-particle molecules and mesic molecules against dissociation is established. 相似文献
5.
V. F. Elesin N. N. Degtyarenko N. V. Matveev A. I. Podlivaev L. A. Openov 《Journal of Experimental and Theoretical Physics》2005,101(1):44-55
The existence of a metastable cluster He 4 * with total spin S = 2 is predicted. The cluster consists of two covalently bound excited spin-polarized triplet He 2 * molecules and is rectangular in shape. The electron wavefunctions, the dependence of the energy He 4 * system on the distance between the He 2 * triplet molecules, the atomic spacing, the frequency spectrum of natural oscillations of the cluster, and other characteristics are calculated from first principles. It is shown that the metastable state is formed if one of the excited He 2 * molecules is in the 3Σ u + state, while the other is in the 3Πg state. The radiation lifetime τ of the metastable cluster He 4 * is calculated; it is found to range from 100 to 200 s, which is much longer than the lifetime τ ≈ 20 s of the triplet molecule He 2 * (3Σ u + ). The height U ≈ 0.5 eV of the potential barrier preventing the departure from the local energy minimum is determined. The energy Eacc ≈ 9 eV/atom accumulated in the He 4 * cluster is calculated; this energy considerably exceeds the energy of known chemical energy carriers. It is shown that the accumulated energy is released virtually completely during decomposition of the He 4 * cluster into individual helium atoms. This means that helium clusters are a promising material with a high accumulated energy density (HEDM). 相似文献
6.
G. V. Sholin A. E. Trenin V. A. Belyaev M. M. Dubrovin A. A. Terent’ev 《Journal of Experimental and Theoretical Physics》2007,104(2):201-209
The anomalous character of threshold properties in the ion-molecule reactions H 2 + + H 2 + → H 3 + + p and H 2 + + H 2 + → H + p + H + p has been theoretically analyzed. It has been shown that these reactions proceed through the formation of the intermediate H 4 ++ complex. Molecules H 2 + in the collision process are described by a chemical model, where the positive charge is concentrated in one of the nuclei. The calculations of the reaction cross sections are in good agreement with the experimental data. It has been shown that the chemical model of the H 2 + molecule can be consistently explained only in terms of dynamic interactions, i.e., polarization forces and van der Waals forces. 相似文献
7.
To identify the structure of emissive tunnel recombination sites in the emulsion microcrystals of silver bromide AgBr(I) with iodine contaminations and to determine the role of an emulsion medium in their formation, the temperature dependence of the luminescence spectra in the range from 77 to 120 K, the kinetics of the growth of the maximum luminescence intensity value at λ ≈ 560 nm, and the luminescence flash spectrum stimulated by the infrared light are investigated. Two types of the AgBr1 – x(I x ) (x = 0.03) microcrystals—namely, obtained in an aqueous solution and on a gelatin substrate—are used in the studies. It is established that the emissive tunnel recombination sites with a luminescence maximum at λ ≈ 560 nm in AgBr1 – x(I x ) (x = 0.03) are the {(I a - I a - )Ag i + } donor–acceptor complexes with the I a - iodine ions located in neighbor anionic sites of the AgBr(I) crystal lattice, next to which the Ag i + interstitial silver ion is positioned. With an increase in the temperature, the {(I a - I a - )Ag i + } sites undergo structural transformation into the {(I a - I a - )Agin+} sites, where n = 2, 3, …. Moreover, the {(I a - I a - )Ag in + } sites (n = 2) after the capture of an electron and hole also provide the tunnel recombination with a luminescence maximum at λ ≈ 720 nm. The influence of an emulsion medium consists in that gelatin interacts with the surface electron-localization sites, i.e., the interstitial silver ions Ag in + , n = 1, 2, and forms the complexes {Ag in 0 G+} (n = 1, 2) with them. The latter are deeper electron traps with a small capture cross section as compared to the Ag in + sites (n = 1, 2) and that manifest themselves in that the kinetics of the luminescence growth in AgBr(I) to a stationary level at λ ≈ 560 nm is characterized by the presence of “flash firing.” At the same time, the luminescence flash stimulated by IR light, for which the Ag in + (n = 1, 2) electron-localization sites are responsible, is absent. It is supposed that the electrons localized on the {Ag in + G+} complexes (n = 2) retain the capability for emissive tunnel recombination with holes localized on paired iodine sites with a luminescence maximum at λ ≈ 750 nm. 相似文献
8.
Experimental limits on the half-lives with respect to the (0ν+2ν) double-beta decay of 130Te to excited states in 130Xe are obtained by using low-background HPGe detectors. At a 90% C.L., they are 1.6×1021, 2.7×1021, and 2.3×1021 yr for transitions to the 2 1 + , 2 2 + , and 0 1 + levels, respectively. 相似文献
9.
M. A. Khodorkovskiĭ A. A. Belyaeva L. P. Rakcheeva P. Yu. Serdobintsev A. A. Pastor A. S. Mel’nikov N. A. Timofeev R. Hallin K. Seigbahn 《Optics and Spectroscopy》2008,104(5):674-685
The spectra of Xe2, XeKr, and XeAr molecules in the range 66 500–68 800 cm?1 are obtained by the methods of (2 + n) and (3 + n) (n = 1, 2, 3) resonance multiphoton ionization during the registration of molecular and atomic ions. The combining of two-and three-photon resonance excitations of Xe2 molecules makes it possible to obtain the spectra caused by transitions from the ground state X0 g + to the excited states of Xe*6s[3/2] 1,2 o Xe1 S 0 molecules both of the even (0 g + , 1 g ) and of the odd (B0 u + , B′1 u , 2 u ) symmetries. The data on the Ω = 2 u state of the Xe2 molecule with the dissociation limit Xe*6s[3/2] 2 o + Xe1 S 0 and on the Ω = 1 state of the XeAr molecule with the dissociation limit Xe*6s[3/2] 1 o + Ar1 S 0 are obtained for the first time. The potential curve of the excited 2 u state of the Xe*6s[3/2] 2 o Xe1 S 0 molecule is repulsive and intersects the potential curve of the B0 u + state of the Xe*6s[3/2] 1 o Xe1 S 0 molecule. In the case of the three-photon excitation, it is observed that all the bands in the spectra of XeKr and XeAr molecules are broadened and are shifted, which indicates that, in an intense light field, the influence of the dynamic Stark effect is significant. 相似文献
10.
N. I. Rukhadze V. B. Brudanin A. A. Klimenko F. Piquemal E. N. Rukhadze Yu. A. Shitov I. Štekl G. Warot 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(6):708-711
Double beta decay (β + EC, EC/EC) of 58Ni is investigated at France’s Modane Underground Laboratory (4800 m water equivalent) using the OBELIX ultralow-background HPGe detector with a sensitive volume of 600 cm3 and a natural nickel sample of ~68% 58Ni with a mass of ~21.7 kg. After preliminary analysis of the experimental data accumulated over ~144 days, new experimental limits are obtained for the 2νβ+EC decay of 58Ni to the 0+ ground state and the 2 1 + , 811 keV excited state of 58Fe, and for the 2νEC/EC decay of 58Ni to the 2 1 + , 811 keV and 2 2 + , 1675 keV excited states of 58Fe. The limits are T1/2(β+EC,0→0+) > 1.7 × 1022 yr, T1/2(β+EC,0→2 1 + ) > 2.3 × 1022 yr, T1/2(EC/EC,0→2 1 + ) > 3.3 × 1022 yr, and T1/2(EC/EC,0→2 2 + ) > 3.4 × 1022 yr. Experimental limit T1/2(0νEC/EC–res, 1918 keV > 4.1 × 1022 yr is obtained for resonant neutrinoless radiative EC/EC decay with an energy of 1918.3 keV. All limits are at 90% CL. 相似文献
11.
A. D. Bykov O. V. Naumenko A. M. Pshenichnikov L. N. Sinitsa A. P. Shcherbakov 《Optics and Spectroscopy》2003,94(4):528-537
An expert system for automatic identification of the complex vibrational-rotational spectra of molecules has been developed. An iteration approach is implemented in this system, in which employment of the exact combination rule is combined with determination of the spectroscopic constants by solving of the inverse problems and comparison of the calculated parameters of spectral lines with the corresponding measured values. In order to calculate the energy levels and the frequencies and intensities of lines, the Watson Hamiltonian, the Padé-Borel approximants, and generating functions are used. The system is based on the application of pattern-recognition algorithms. Recognition training makes it possible to obtain the required flexibility of the system and to use different methods of identification based on the application of combination rules both for the analysis of strong bands and for the assignment of weak single lines. The system developed can be used to analyze the spectra of the C s and C 2V molecules, as well as employ the calculated spectrum of a molecule of any type prepared in advance. This system was successfully used to identify the H 2 16 O, H 2 17 O, H 2 18 O, D2O, HDO, H 2 32 S, H 2 34 S, and H 2 33 S and molecules. 相似文献
12.
O.?E.?Kvyatkovski? 《Physics of the Solid State》2009,51(5):982-990
Ab initio calculations of the optimized geometry and the electronic structure of lattice defects in incipient perovskite ferroelectrics SrTiO3 and KTaO3 are performed in the framework of the density functional theory. The results are presented for the Li+ impurity ion at the A site in the KTaO3 and SrTiO3 ferroelectrics; the Mn2+, Cd2+, Ca2+, Mg2+, and Zn2+ ions at the A site and the Mn4+ and Mg2+ ions at the B site in the SrTiO3 compound; and the MN Ti 2+ -V O and Mg Ti 2+ -V O complexes in the SrTiO3 ferroelectric. The results are obtained by the cluster method with allowance made for the structural relaxation initiated by the defect and, for nonisovalent substitutional impurities, with due regard for the charge and spin states of the defect. It is established that the Ca Sr 2+ , Cd Sr 2+ , Mn Ti 4+ , and Mg Ti 2+ ions have a stable central position, whereas the Li K + ion in the KTaO3 compound and the Li Sr + , Mn Sr 2+ , and Zn Sr 2+ defects in the SrTiO3 ferroelectric are off-center ions. The shape of the multiminimum adiabatic potential and the parameters of dielectric relaxators (activation barrier, dipole moment) for polar defects are obtained. The electronic impurity levels are determined for the Li Sr + and Mg Ti 2+ neutral defects. 相似文献
13.
S. E. Maksimov N. Kh. Dzhemilev S. F. Kovalenko V. I. Tugushev O. F. Tukfatullin Sh. T. Khozhiev 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(2):101-104
Results from a comparative SIMS study of the fragmentation of metal clusters sputtered with atomic Xe+ and molecular SF5+ ions are presented. It is shown that the average decay rate constants and, hence, the excitation energies of clusters of the same stoichiometry do not depend on the type of bombarding ions. 相似文献
14.
Three imidazoline-type nitroxide biradicals of the similar composition R 5 NO –CH=N–N=CH–R 5 N , B1, R 5 NO –CH=N–N=C(CH3)–R 5 N , B2, and R 5 N –C(CH3)=N–N=C(CH3)–R 5 N , B3, with R 5 N and R 5 NO denoting, respectively, the nitroxide rings 1-oxyl-2,2,5,5-tetramethyl-3-imidazoline and 1-oxyl-2,2,5,5-tetramethyl-3-N–oxide imidazoline, have been studied by X-band electron paramagnetic resonance (EPR) spectroscopy. Variations of the intramolecular electron spin exchange in these biradicals dissolved in ethanol and the room temperature ionic liquid bmimBF4 were characterized as a function of temperature by means of the analysis of the EPR lines shape. Thermodynamic parameters of the conformational rearrangements in ethanol were calculated. Analyzing the EPR spectra of these biradicals in bmimBF4, it was revealed that the two-conformational model does not describe their conformational transitions. Moreover, the observed EPR spectra are not central symmetric especially at low temperatures that cannot be described and explained in the framework of the current theory of the intramolecular spin exchange. Probable reasons of this “strange” behavior are discussed. 相似文献
15.
A. M. Zimin V. A. Krupin V. I. Troynov L. A. Klyuchnikov 《Physics of Atomic Nuclei》2015,78(12):1319-1325
The experiments on recording molecular emission in the edge plasma of the T-10 tokamak are described. To obtain reliable spectra with sufficient spectral, temporal, and spatial resolution, the optical circuit is optimized for various experimental conditions. Typical spectra measured in two sections of the tokamak are shown. It is shown that, upon varying the parameters of the discharge, the molecular spectrum not only changes significantly in intensity but also undergoes a qualitative change in the rotational and vibrational structure. For a detailed analysis, we use the Fulcher-α system (d3Πu–a3Σ g + ) of deuterium in the wavelength range from 590 to 640 nm. The rotational temperatures of ground state X1Σ g + and upper excited state d3Πu are estimated by the measured spectra. 相似文献
16.
High-frequency broad-band (65–240 GHz) EPR is used to study impurity centers of bivalent chromium in a CdGa2S4 crystal. It is found that the EPR spectra correspond to tetragonal symmetry. The spin Hamiltonian H = βB · g · S + B 2 0 O 2 0 + B 4 0 O 4 0 + B 4 4 O 4 4 with the parameters B 2 0 =23659±2 MHz, B 4 0 =1.9±1 MHz, |B 4 4 |=54.2±2 MHz, g‖=1.93±0.02, and g⊥=1.99±0.02 is used to describe the observed spectra. It is concluded that chromium ions occupy one of the tetrahedrally coordinated cation positions. 相似文献
17.
Yu. N. Ovchinnikov 《Journal of Experimental and Theoretical Physics》2004,98(1):162-169
The conductivity and the distribution of electric field, current, and charge density in a periodic two-component system composed of rhombs with an arbitrary vertex angle of 2α are investigated. The effective conductivity of such a medium is represented by a tensor with components σ eff 11 (α) and σ eff 22 (α) in the principal axes that satisfy the Dykhne relation σ eff 11 (α) σ eff 22 (α)=σ 1σ2, where σ1, σ2 are the isotropic conductivities of media 1 and 2. In addition, the relation σ eff 22 (α)=σ eff 11 (π/2?α) is satisfied. The principal axes are directed along the diagonals of the rhombs. It is shown that there are three lines in the rectangle 0<α ≤π/2,?1<Z<1((Z=σ1?σ2)/(σ 1+σ2)) on which the charge density is expressed in terms elliptic functions. An explicit expression is obtained for all physical quantities on these lines. 相似文献
18.
V. K. Nikulin M. B. Trzhaskovskaya 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(10):1201-1206
The probabilities of K-shell ionization in daughter atoms during the α-decay of extensively studied 84Po isotopes and superheavy 117 294 Ts, 113 286 Nh, 109 278 Mt, 105 270 Db, 102 253 No, 100 249 Fm, and 111 272 Rg nuclei are calculated. Monopole and dipole terms are considered. More accurate expressions for α-particle tunneling through the atomic Coulomb barrier are derived. The electron wave functions are calculated using the relativistic Dirac–Fock method. The results are essential for processing the spectra analyzed in combined α-, γ-, and conversion-electron spectroscopy. 相似文献
19.
The spectral and power characteristics of radiation of the second positive system of nitrogen (C 3Π u → B 3Π g ) in Ar-N2 and Ar-N2-Cl2 mixtures excited by barrier discharge have been studied experimentally. Addition of argon to N2 increased the radiation power by sixfold. In the triple mixture Ar-N2-Cl2 = 210/0.5/0.005, minor chlorine additions increased the intensity of the C 3Π u → B 3Π g transition by 26% compared to Ar-N2 mixtures. Radiation power density of 2.7 mW/cm2 has been achieved. In both binary and triple mixtures, the second positive system of nitrogen was the major contributor to radiation, while the contributions of the fourth positive system of N 2 * (D 3Σ u + → B 3Π g ), the Vegard-Kaplan transition of N 2 * (A 3Σ u + → X 1Σ g + ), and the D′ → A′ band of Cl 2 * were negligibly small. 相似文献
20.
The Λ 7 He hypernucleus is considered within the Λ 5 He + n + n cluster model. The hyperon—nucleon interaction is described by a one-boson-exchange potential that is constructed on the basis of the NSC97f model. Phenomenological potentials are used to describe the αΛ and αN interactions. For the Λ 5 Hen interaction, use is made of the folding-model potential. The calculations of the hyperon binding energy in the ground state of the Λ 7 He hypernucleus on the basis of Faddeev equations in configuration space yield a result (5.35 MeV) that agrees well with preliminary experimental data (5.4 MeV). The problem of calculating the hyperon binding energy within the three-body approach is discussed. In calculating the energy spectrum of Λ 7 He, use is made of a version of the method of analytic continuation in the coupling constant. Low-lying excited states of this nucleus can be classified as an analog of the corresponding states of the 6He nucleus with allowance for the clustering of the Λ 5 He+n+n system in the 6He(J π)+Λ(s) form. 相似文献