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1.
The kinetic (K 4 0 (n) and K 3 0 (n)) and potential (V 4 0 (n) and V 3 0 (n)) energies of 4He and 3He atoms have been found from the law of corresponding states and the experimental data on the dependence of the ground-state energies E 4 0 (n) and E 3 0 (n) on the density of the isotopes 4He and 3He. In the approximation of structureless quantum liquid, the potential energies are equal, V 4 0 V 3 0 (n) = (n), and the kinetic energies are inversely proportional to the atomic mass, $K_4^0 (n) = \frac{3} {4}K_3^0 (n)$ . The potential energy given by the expression V 0 = 4E 4 0 ? 3E 3 0 to a high accuracy is linear in the density n, which is associated with nearly an absence of short-range order in liquid helium. The kinetic energy of liquid 4He is given by the expression K 4 0 = 3(E 3 0 ? E 4 0 ), which agrees with the experimental data on neutron scattering in liquid 4He. The quantities K 4 0 (n) and K 3 0 (n) determine the scale of all thermodynamic characteristics in the temperature range where the effects of the particle statistics can be neglected. 相似文献
2.
The properties of the low-lying energy states for the 100Mo isotope is investigated within the framework of the proton-neutron interacting model IBM2.By considering the relative energy of the d proton boson to be diferent from that of the neutron boson and taking into account the dipole interacting among like-boson LπLπand LνLν,the low-lying energy spectrum is reproduced well.Particularly,the relative position of the energies for 2+1,0+2,2+2 and 4+1states shifted correctly fit the experimental data.The electromagnetic properties,including the key observable B(E2)reduced transition branching ratios and the E2 reduced matrix elements of the experimental data,are well described.Our calculations show possible shape coexistence in the 100Mo nucleus. 相似文献
3.
We have performed microscopic cluster studies of light∑-hypernuclei based on effective nucleon-nucleon and two different sigma-nucleon interactions. Our calculation confirms a bound 0+ state in ∑ 4 He and ∑ 4 H, but reveals no evidence for levels in other partial waves. We have investigated the ∑ 8 Li and ∑ 8 Be hypernuclei in a microscopic 3-cluster approach. For both hypernuclei, our calculation shows that the lowest levels in the partial wavesJ=0–4 are bound or quasibound states of collective nature and show a strong α ∑ 4 H and α + ∑ 4 He clustering. These levels form a sequence of states which can be well interpreted as arising from a rotatingα+ ∑ 4 H orα+ ∑ 4 He di-molecule. Our results are compared to those of similar studies for lightΛ-hypernuclei which do not show evidence for this kind of collective degrees of freedom. 相似文献
4.
S. E. Maksimov S. F. Kovalenko O. F. Tukfatullin Sh. T. Khozhiev N. Kh. Dzhemilev 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(5):527-530
The mass distributions and fragmentation routes of Nb n O m + and V n N m + clusters sputtered from an metal surfaces with Xe+ ions under O2 pressure of P = 4?5 × 10?3 Pa in a bombardment chamber are studied by means of secondary ion mass spectrometry. The spectra of kinetic energy release distribution (KERD) are measured for the most probable routes of the fragmentation of Nb n O m + and V n N m + and clusters, on the basis of which the activation energies of the decomposition (dissociation) of Nb n O m + and V n N m + clusters are determined within the model of evaporative ensemble and the theory of monomolecular reactions. The results show the closeness of the numerical values of dissociation energies derived using both models. 相似文献
5.
S. N. Morozov U. Kh. Rasulev 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(6):516-519
The emission of Si n + (n = 1–11) cluster ions and Si n X m + (X stands for B or Sb) polyatomic ions when bombarding a single silicon crystal with Sb m + (m = 1–4) cluster ions with energies E 0 = 3–12 keV is studied. Considerable nonadditive enhancement of the yield of Si n + cluster ions and most polyatomic ions is observed when the number of atoms in the bombarding cluster ions is increased. The sensitivity enhancement factor for detecting boron impurities is as high as 50 when the cluster-SIMS-molecule technique is applied. 相似文献
6.
The ΛΛ 6 He and Λ 9 Be hypernuclei are treated as the S=0, T=0 (for the former) and S=1/2, T=0 (for the latter) bound states of the three-cluster systems ΛΛα and Λαα, respectively. The cluster-reduction method is used to solve the s-wave differential Faddeev equations for these systems. On the basis of the MT I–III model, the ΛΛ interaction potential is specified in the form $V_{\Lambda \Lambda } = \frac{2}{3}V_{NN} $ . Phenomenological potentials are used to describe Λα and αα interactions. The binding energies of the ΛΛ 6 He and Λ 9 Be hypernuclei and the parameters of low-energy Λ-hyperon and α-particle scattering on a Λ 5 He hypernucleus are calculated. It is shown that the proposed ΛΛ interaction potential makes it possible to reproduce faithfully the binding energy of the ΛΛ 6 He hypernucleus and that scattering in the Λ Λ 5 He system is similar to neutron scattering on a deuteron. 相似文献
7.
Vikram S. Kushawaha 《Zeitschrift für Physik A Hadrons and Nuclei》1983,313(3):155-160
A laser induced charge transfer from Na(3p) to hydrogen-ions at different kinetic energies has been studied. An enhancement factor of about 90% in the production rate of Lyman-α radiation has been demonstrated to occur only with H+ and Na(3p) atoms reaction; no enhancement was observed with either H 2 + or H 3 + ions. Absolute cross-section for the production of Lyman-α radiation during the collision of H+, H 2 + and H 3 + ions and Na(3p) and Na(3s) atoms have been measured in the energy range 1–600eV. The charge exchange reactions involving hydrogen-ions and Na(3p) atoms created by two different methods have also been compared. 相似文献
8.
V. B. Kopeliovich 《JETP Letters》2012,96(4):210-214
The binding energies of neutron-rich strangeness S = ?1 hypernuclei are estimated in the chiral soliton approach using the bound state rigid oscillator version of the SU(3) quantization model. Additional binding of strange hypernuclei in comparison with nonstrange neutron-rich nuclei takes place at not large values of atomic (baryon) numbers, A = B ?? ??10. This effect becomes stronger with increasing isospin of nuclides, and for the ??nuclear variant?? of the model with rescaled Skyrme constant e. Binding energies of ?? 8 He and recently discovered ?? 6 H satisfactorily agree with data. Hypernuclei ?? 7 H, ?? 9 He are predicted to be bound stronger in comparison with their nonstrange analogues 7H, 9He; hypernuclei ?? 10 Li, ?? 11 LI, ?? 12 Be, ?? 13 Be, etc. are bound stronger in the nuclear variant of the model. 相似文献
9.
A. V. Bulgakov O. F. Bobrenok V. I. Kosyakov I. Ozerov W. Marine M. Hedén F. Rohmund E. E. B. Campbell 《Physics of the Solid State》2002,44(4):617-622
Experimental results on the gas-phase formation of neutral and cationic phosphorus clusters are presented. The clusters were synthesized by visible (532 nm) or UV (193 nm) laser ablation of crystalline red phosphorus under high vacuum conditions and were analyzed using TOF mass spectrometry. Neutral Pn clusters produced by 532-nm ablation are found to be even-numbered while P n + cations are mainly odd-numbered, with P 7 + and P 21 + being the most abundant ions. For UV laser ablation, stable compound clusters, neutral P7H3 and P23H5, and cations P23H 6 + were synthesized for the first time. The formation of Pn clusters by thermal vaporization of red phosphorus into a cold He gas was also investigated and only small clusters (n<6) were found. Possible structures of the observed phosphorus clusters, as well as their formation mechanisms under different conditions, are discussed. 相似文献
10.
11.
For collision energies between 100 and 500 eV the collision induced dissociation of H 3 + colliding with H2, He and Kr gas targets was measured. We obtained total cross sections and angular distributions of the charged collision fragments for the main reaction channels. H 3 + +H2→H++2H2 and H 3 + +H2→H 2 + +H2+H. An analysis of the kinetics yields that the dissociation proceeds via vibrational-rotational excitation of H 3 + by mutually induced dipolmoments. 相似文献
12.
Coulomb excitation byα-particles of vibrational-like states in even-mass rare-earth nuclei is used to determine the reduced transition probabilitiesB(E2; 0 gs + →2 γ + ),B(E2; 0 gs + →2 β + ),B(E2; 2 gs + →0 β + ) andB(E2; 0 gs + →3 oct ? ) in150Nd,152, 154Sm,154, 158Gd,164Dy and166Er. TheB(Eλ; 0 gs + →I=λ)-values range from 2.4 to 6.5 single-particle units for transitions to the 2 γ + -states, 0.8 single-particle units for the 2 β + -states and from 14.1 to 21.7 single-particle units for the 3?-states. 相似文献
13.
A. E. Stuchbery H. H. Bolotin C. E. Doran I. Morrison L. D. Wood H. Yamada 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(4):669-674
The gyromagnetic ratios of the 4 1 + , 6 1 + , and 2 2 + states in186W were measured relative to that of the 2 1 + level by means of the transient field implantation perturbedγ-ray angular distribution technique. The nuclei in the states of interest were Coulomb excited using a beam of 220-MeV63Cu projectiles and recoiled swiftly through a thin, polarized Fe foil. The present measurements yielded ratiosg(4 1 + )/g(2 1 + )=1.04±0.07,g(6 1 + )/g(2 1 + )=1.03 ±0.20 andg(2 2 + )/g(2 1 + )=0.63±0.13. The sizable disparity between the measuredg-factors of the ground- and excited-band is examined within the context of the interacting boson approximation model. 相似文献
14.
N. Kh. Dzhemilev S. E. Maksimov Sh. T. Khojiev 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2014,8(5):1063-1067
The energy spectra of Si n O m ? clusters sputtered from Si targets by Xe+ ions with O2 pumping onto a bombarded surface, as well as by O 2 + ions, are studied. It is shown that the form of the Si n O 2n+1 ? energy distributions does not depend on the experimental conditions. Significant differences in the energy spectra of O and Si monomers as compared to Si n O 2n+1 ? clusters are revealed. The mentioned features of the energy distribution of Si n O m ? clusters are explained within the framework of the statistical recombination mechanism of their formation in combinatorial synthesis processes. 相似文献
15.
C. G. Lindén I. Bergström J. Blomqvist C. Roulet 《Zeitschrift für Physik A Hadrons and Nuclei》1978,284(2):217-231
High-spin states in204Pb were populated in the204Hg(α,4n) reaction using α-particles in the energy region 42–51 MeV. Prompt and delayedγ-rays as well as conversion electrons were studied in addition to excitation functions, angular distributions andγ-γ coincidences. In this way a stretched cascade ofγ-rays from a level at 8125.9 keV was found to feed the previously known isomeric 9? level at 2185.7 keV. Spins and parities were established for levels up to and including a 19? level at 6098.0 keV. The levels with c= 172212; and 19? at excitation energies of 5664.3 and 6098.0 keV are likely to be due to the simplep 1 2/s-1 i 13 2/?3 andf 5 2/?1 i 13 2/?3 configurations. The agreement between calculated and experimental energies for all observed levels in the regionJ=9–19 is very good in cases where the empirical two-particle interactions used are satisfactorily well known. Above the 19? level there are three weakly populated levels at 7402.1, 7849.2 and 8125.9 keV, which are likely to haveJ≥20. None of these energies agrees with the calculated value 7695±20 keV for the 20+ state of thei 13 2/?4 configuration which has the highest angular momentum produced by the four valence neutron holes. This apparent anomaly can be understood if the yrast levels withJ≥20 have angular momentum contribution from the core. It seems likely that the states at 7402.1, 7849.2 and 8125.9 keV are due to proton core excited states of the typeπh 9/2 h 11 2/?1 ×νp 1 2/?2 i 13 2/?2 withJ π=20+ andJ π=21+ andπh 9/2 h 11 2/?1 ×νp 1 2/?1 f 5 2?1 i 13 2/?2 withJ π=22+ or 23+, respectively. The state at 8126 keV has the highest energy so far directly observed in a stretched cascade ofγ-rays from the decay of a heavy nucleus produced in (α, xn) reactions. 相似文献
16.
I. Blomqvist B. Bülow A. Fredrikson B. Johnsson G. G. Jonsson K. Lindgren M. Nilsson R. Petersson O. Glomset N. Freed W. Rhodes 《Zeitschrift für Physik A Hadrons and Nuclei》1978,284(3):313-317
The lifetime of the 331.3 keV 0 2 + state in100Zr has been measured at the gas-filled recoil separator for fission products JOSEF. By observing the delayed coincidences between theβ-particles populating the level and theE0 conversion electrons from its decay into the ground state, a half-life of 3.37±0.30 ns has been obtained. From the measured lifetime and the relative intensities of the 0 2 + →0 1 + and 0 2 + →2 1 + transitions, values of 0.493±0.015 for theE0 strength parameterρ, and of 16 single particle units forB(E2,2 1 + → 0 2 + ) have been deduced. The enhanced nature of theE0 transitions suggests mixing of the 0 1 + and 0 2 + states which may be estimated by comparing the experimentalB(E2) values for the 2 1 + →0 1 + and 2 1 + →0 2 + transitions with the predictions of the asymmetric VMI model. 相似文献
17.
A. A. Okhunov 《Physics of Atomic Nuclei》2006,69(4):593-597
The nonadiabaticity of E0 transitions from 0 2 + states and 2 1 + bands in 156Dy is examined within a phenomenological model that takes into account the mixing of K π = 0 1 + , 0 2 + , 0 3 + , 2 1 + states and 1+-bands. It is shown that the nonadiabaticity of E0 transitions is due primarily to the mixing of 0 2 + and 0 3 + bands. 相似文献
18.
I. Alfter E. Bodenstedt B. Hamer J. van den Hoff W. Knichel H. Münning S. Piel R. Sajok J. Schüth 《Zeitschrift für Physik A Hadrons and Nuclei》1993,345(3):273-283
Theg-factors of the four lowest states of the ground state rotational band of158Dy have been determined asg(2 1 + )=+0.362(23),g(4 1 su+ )=+0.340(20),g(6 1 su+ )=+0.207(36) andg(8 1 su+ )=+0.21(11). Theg-factors of the 2+ and 4+ states were measured by the IPAC method with radioactive samples of 2.4 h158Er in external magnetic fields. To investigate the higher states, for the first time an on-line γ—γ IPAC experiment was performed with the reaction156Gd(α, 2n)158Dy by use of the static hyperfine field of DyGd. 相似文献
19.
The time dependences of the ion number densities in the pink afterglow of nitrogen, as represented by the ion wall currents, have been measured. The ions were extracted through an orifice from a flow system and analysed by a quadrupol mass spectrometer. It has been found thatN 2 + ions are dominating in the early afterglow. With the beginning of the ionization processN 3 + and at pressure >6 TorrN 4 + become the majority ions. The ratio of the number densities(N 3 + )/(N 2 + ) reaches a maximum during the increase of the ionization processes before the maximum is reached. This behaviour suggestsN 3 + ions to be the primary ions created by the ionization processes. The time dependences of the ion number densities (N 2 + ), (N 3 + ) and(N 4 + ) are found to vary similar, showing that the ions are strongly coupled by conversion processes. The conversion processes are discussed. In the maximum of ionization at a total pressure of 4.4 Torr the ratios of the number densities of the afterglow ions (N 2 + )∶(N 3 + )∶(N 4 +) are 1∶1.9∶0.64. 相似文献
20.
I. Bergström J. Blomqvist C. J. Herrlander C. G. Lindén 《Zeitschrift für Physik A Hadrons and Nuclei》1976,278(3):257-264
Using the204Hg(α, pn)-reaction andα-particles of energies 39–55 MeV, we have found an isomeric 3.6 min 12? state in206Tl at 2,642.9 keV which has the two-hole configurationπh 11 2/?1 vi 13 2/?1 The 12? state decays mainly by anE5 transition of energy 1,021.4 keV to a 7+ state at 1,621.5 keV whose main configuration isπs 1 2/?1 vi 13 2/?1 There is, in addition, evidence for a weak 565 keVM 4 branch to an 8+ state at 2,078 keV whose main configuration should beπh 11 2/?1 vf 5 2/?1 . The 7+ state decays by a stretched cascade ofγ-rays to states of the following values ofJ π and excitation energy: 5 ? + , 1,405.4 keV; 4?, 952.1 keV; 2?, 265.8 keV and 0?, 0 keV. The main configurations of these states areπh 11 2/?1 vp 1 2/?1 ,πd 3 2/?1 vf 5 2/?1 ,πd 3 2/?1 vp 1 2/?1 andπs 1 2/?1 vp 1 2/?1 respectively. From the nuclear masses of208Pb,207Pb,207Tl, and206Tl and the experimental excitation energies it is possible to obtain the proton hole-neutron hole interaction in206Tl. This interaction is compared with the calculations of Kuo and Herling and the discrepancies are discussed. The 12?→8+ M4 transition rate is reduced because of destructive interference between the protonh 11/2→d 3/2 and the neutroni 13/2→f 5/2 contributions. The magnitude of the reduction is accurately reproduced by the wave functions of Kuo and Herling. The 12?→7+ E5 transition rate is about twice as large as the single-holeπh 11 2/?1 πs 1 2/?1 transition rate. This deviation is fully explained by the configuration admixtures in the 7+ state, given by Kuo and Herling. 相似文献