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1.
The two emission lines, Kα1α3h and Kα2α3h resulting from the two-electron transitions 1s?2 → 2s?1 2p32?1 and 1s?2 → 2s?1 2p12?1 were resolved for elemental nickel. Their measured energies agree well with calculations. Their relative intensity I(Kα1α3h)/I(Kα2α3h) ≈ 34 and their intensity relative to that of the Kα diagram lines is about 10?4. This is some 104 times larger than both theoretical results and the results of ion-atom collision experiments.  相似文献   

2.
The sound velocities in GeS2 glass have been measured by means of ultrasonic interferometry as a function of temperature or pressure up to 1.8 kbar. The bulk modulus Ks = 117.6 kbar and shear modulus G = 60.60 kbar were obtained for GeS2 glass at 15°C and 1 atm. The temperature derivatives of both sound velocities and elastic moduli are negative :
(1?T)
p =
?1.54 × 10?4 kmsec
°C,
(1?T)
p =
?1.27× 10?4 kmsec
°C and
(?Ks?T)
p =
?1.27 × 10?2kbar°C
,
(?G?T)
p = ?1.23 × 10?2 kbar/°C,
(?Y?T)
p = ?2.93 × 10?2 their pressure derivatives are positive:
(1?P)
T = 4.43× 10?2km/kbar,
(1?P)
T =
0.633 × 10?2kmkbar
and (?Ks?P0)T=6.81,
(?G?P)T
= 1.03, (?Y?TT= 3.57. The Grüneisen parameter, γth= 0.298, and the second Grüneisen parameter, δs = 3.27, have also been calculated from these data. The elastic behavior of GeS2 glass has proved to be normal despite the structural similarity among the tetrahedrally coordinated SiO2, GeO2 and GeS2 glasses.  相似文献   

3.
Using the re-equilibration kinetic method the chemical diffusion coefficient in nonstoichiometric chromium sesquisulfide, Cr2+yS3, has been determined as a function of temperature (1073–1373 K) and sulphur vapour pressure (10?104 Pa). It has been found that this coefficient is independent of sulphur pressure and can be described by the following empirical equation: D?Cr2+yS3=50.86 exp(-39070 cal/mole/RT) (cm2s?1). It has been shown that the mobility of the point defects inCr2+yS3 is independent of their concentration and that the self-diffusion coefficient of chromium in this sulfide has the following function of temperature and sulphur pressure: DCr=2.706×102P?14.85S2exp(-56070 cal/mole/RT). (cm2s?1).  相似文献   

4.
The complex polar Kerr effect (rotation and ellipticity) of magnetite single crystals has been measured at room temperature between 0.5 and 4.3 eV. From the magneto-optical data and the optical constants, the off-diagonal elements (?xy) of the dielectric tensor has been derived. Three well separated magneto-optical transitions have been indentified. At about 0.75 eV one strong magneto-optical structure with a diamagnetic line shape is assigned to a 3d6→3d5(6A1g) 4s transition from Fe2+ in octahedral sites. Two other structures with paramagnetic line shapes near 1.85 and 2.90 eV are assigned to the orbital promotion processes 3d6(Fe2+oct)→3d5(4T1g) 4s and 3d5(Fe3+tet)→3d4(5T2) 4s, respectively, which take into account Fe 3dn?1 final state effects.  相似文献   

5.
We report low temperatures ESR and Superconductivity experiments on Nd3+ and Gd3+ in the superconducting cubic intermetallic compound ZrIr2. The ratio of the squares of the effective 4f-conduction electron exchange parameters corresponding to Nd3+ and Gd3+ (J2s-NdJ2s-Gd) were extracted both from the thermal broadening of the ESR linewidths and from the initial depression of the superconducting critical temperature, and were found to be comparable. Nd3+ was found to have a larger exchange parameter than of Gd3+.  相似文献   

6.
Concentration dependent diffusion coefficients for 45Ca2+ and 85Sr2+ in purified KCl were measured using a sectioning method. KCl was purified by an ion exchange — Cl2?HCl process and the crystals grown under 16 atmosphere of HCl. The tracers were purified on small disposable ion exchange columns to remove precessor and daughter impurities prior to use in a diffusion anneal. Isothermal diffusion anneals were made in the temperature range from 451% to 669%C. At temperatures above 580%C (the lowest melting eutectic in this system) diffusion was from a vapor source: below 580%C surface depositied sources were used. The saturation diffusion coefficients. enthalpies and entropies of impurity-vacancy associations were calculated using the common ion model for simultaneous diffusion of divalent ions in alkali halides. In KCl the saturation diffusion coefficients DS(ca) and Ds(Sr) are given by
Ds(Ca) = 9.93 × 10?5 exp(?0.592 eVkT)cm2sec
(1) and
Ds(Sr) = 1.20 × 10?3 exp(?0.871 eVkT)cm2sec
(2) for calcium and strontium, respectively. The Gibbs free energy of association of the impurity vacancy complex in KCl for calcium can be represented by
Δg(Ca) = ?-0.507 eV + (2.25 × 10?4eV%K)T
(3) and that for strontium by
Δg(Sr) = ?0.575 eV + (2.90 × 10?4eV%K)T
. (4)  相似文献   

7.
The low temperature mobility μ limited by charged impurities is calculated by solving the equation for the relaxation rate previously derived. The calculated μ behaves like μ = 2.03 κ2 (kBT)32e?3z?2ns?1m1?12 In [38.2κ2m112 (kBT)52/z2 e4h?ns] for lowest concentrations ns<1011cm?3 for Ge and
μ = 0.360h?12κ(kBT)14(ze)?1ns?12m1?34
for intermediate concentrations ns ~ 1012?1014cm?3.  相似文献   

8.
N. Kimura 《Nuclear Physics B》1984,246(1):143-156
Masses of all the glueballs which are created by 6- or 7-link operators are calculated to order g?8 in pure SU(3) hamiltonian lattice gauge theory. Several low-lying states are found with masses m(0++1)~ 1.4 ms, m(0++7) ~ 1.7 ms (1 and 7 stand for radial excitations and ms is the mass of the lowest 0++ state), m(0??) ~ 2.2 ms, m(1+?1) ~ m(1.6 ms, m(1?+) ~ 1.8 ms, m(1??) ~ 2.2 ms and m(2++) ~ 1.3 ms. These values are obtained at the point g?2 ? 0.8, which lies near the scaling region.  相似文献   

9.
The non-selective nature of the (α, nγ) reaction has been used to complement information from charged-particle reactions on the level structure of 88Y and 90Y. The γ-ray spectra were recorded with a 25 cm3 Ge(Li) detector at 90° to the beam using primarily targets of 85Rb2CO3 and 87Rb2CO3 and α-particle energies of 11.8, 12.2 and 13.0 MeV. The resulting transitions were accommodated in level schemes that involved primarily the following shell model configurations: p12)1g92)?1, g92)?1g92)1, p12)1p12)?1, f52)?1g92)?1 in 88Y and p12)1d52)1, πg(92)1d52)1,p12)1s12))1 in 90Y.  相似文献   

10.
An ab initio SCF and CI treatment of the electronic spectrum of ammonia in both the pyramidal and planar conformation is reported which employs an [8, 6, 14, 1] AO basis of near Hartree-Fock quality; the ground state CI energy obtained for the equilibrium conformation is ?56.4241 a.u. In addition, further calculations have been carried out at the SCF level to study various photodissociation reactions of NH3. The calculated CI transition energies are seen to agree with corresponding experimental values to within 0.0–0.3 eV, usually in the 0.1-eV range. Photodissociation to the NH2 (2B?1) + H(2S) products is confirmed thereby to proceed via the A? 1a″2 → 3s state of ammonia, but contrary to earlier speculation it is found that the transformation between reactant and products is already satisfactorily described at the SCF or orbital level, i.e., a Rydberg 3s of NH3 is seen to be gradually converted into a pure hydrogenic 1s species as dissociation proceeds. In addition the photolysis of NH3 to NH2(2A1) + H(2S) is argued to occur via the C? 1a″2 → 3pz 1A′1 state and as such is seen to be a symmetry allowed process, in contrast to the previous assignment involving the B? 1a″2 → 3px, y 1E″ species. Finally an attempt is made to analyze the mechanisms of various NH + H2 photodissociation processes with the help of SCF calculations and symmetry arguments for various higher-lying excited states of ammonia.  相似文献   

11.
The difference of the cross sections for deep inelastic scattering of muons with average momenta 21 GeV/c with right and left helicity at large angles, i.e., with large momentum transfer, has been measured. No statistically-significant dependence of cross sections on the longitudinal polarization of muons has been found, i.e. no parity-nonconservation effects in deep inelastic μN interaction have been observed. The magnitude of the cross-section asymmetry R = [〈σR〉 ? 〈σL〉][〈σR〉+ + 〈σL〉] may be represented as R = βQ2〉 = (? 4 ± 6) × 10?3Q2, (GeV/c)2〉. The limitations Go(μ) = (+ 6 ± 10)G have been obtained for the constant Go(μ) of vector-axial interaction (Go(μ)2) [μγα(1 + γ5)μ] Jαo (hadron, V-A).  相似文献   

12.
Collisions between two excited atoms leading to an increase in the excitation energy of the particles have been under investigation. All measurements were made in the afterglow of gas-discharge plasma. The cross sections of the following reactions have been determined: Hg(63P012) + Hg(63P012) → Hg7 + Hg(61S0), Hem (21,3S) + Xem(3P0,2) → (Xe+)1 + He0 + e. The cross section of the first reaction for different transitions lies in the region (2?35) × 10?15 cm2 and the cross section of the second, in (0.2?2.4) × 10?16 cm2. Possible systematic errors and the role of cascade transitions are discussed. Cross sections of the Penning reaction Hem + Xe0 → He0 + Xe+ + e have also been measured. The result is σ (23S) = (1.4 ± 0.2) × 10?15 cm2, σ (21S) = (1.2 ± 0.3) × 10?15 cm2.  相似文献   

13.
Energies and dipole matrix elements have been calculated for He, Li, Be, B, C, N, O, F, and Ne-like ions (configurations 1s22sn12pn2?1s22sn1?12pn2+1). The Hartree-Fock energy, the correlation energy, and relativistic corrections were taken into account. Relativistic corrections were obtained by computing the entire quantity HB. Numerical results are presented for energies of the terms in the form
E=E0Z2 + ΔE1Z + ΔE2 + 1Z ΔE3 + α24 (E0pZ4 + ΔE1pZ3)
, and for the fine structure of the terms in the form
〈1s22sn12pn2LSJ|HБ|1s22sn1′2pn2′L′S′J〉=(?1)L+S′+JLSJS′L′1 × α24 (Z?A)3[E(0)(Z ? B)+Ec0]+(?1)L + S′ + JLSJS′L′2α24 (Z?A)3Ecc
. Dipole matrix elements are required for calculation of oscillator strengths or transition probabilities. For the dipole matrix elements, two terms of the expansion in 1Z have been obtained. Numerical results are presented in the form P(a, a′) = (a/Z)[1 + (τ/Z)].  相似文献   

14.
15.
From the scaling law for the s-channel partial wave amplitudes, which guarantees simultaneously t-channel unitarity at threshold t = 4μ2 and s-channel unitarity, we derive: (i) The intercept α(0) of the Pomeron is always one, if α(4μ2) > 1. (ii) The total and the elastic cross sections are bounded from below for s → ∞.
σtot ? O((logss1)2δ(4μ2)), σel ? O((logss1)4δ(4μ2)?1)
where α(4μ2) and δ(4μ2) are the position and the type of te Pomeron singularity (J ? α(4μ2))?1?δ(4μ2) at t = 4μ2. (iii) The type of the Pomeron singularity δ(4μ2) is restricted: either δ(4μ2) ? 12 or δ(4μ2) ? 12.  相似文献   

16.
The fluorescence and absorption spectra of Eu3+ in K5Eu(MoO4)4 have been measured at 300 K and 77 K. The fluorescence lifetime of the 5D0 state is 1.4 ms at 300 K. The largest cross section σ(5D07F2(4)) = 1.3 × 10?21 cm2 and the removal of degeneracies require to replace the nearest neighbour D3d symmetry of Eu3+ by the effective symmetries C1, C2 and Cs of the whole unit cell. It is shown that C1 dominates because of the statistical distribution of K+ and Eu3+. The corresponding inhomogeneous broadening is observed at 77 K.  相似文献   

17.
18.
A forward dispersion relation cannot be applied to charged particle scattering amplitudes unless the influence of the Coulomb interaction is explicitly considered. Earlier studies have shown how Coulomb effects can be taken into account when direct (s-channel or bound-state) poles are investigated. In this paper we extend the Coulomb modification to include I = 0 exchange (u-channel) processes as well. We then apply a forward dispersion relation to empirical d + α, p + d and n + d elastic scattering amplitudes which contain both direct and exchange poles with and without Coulomb effects. We obtain detailed and model-independent information on the following vertices: 6Li-α-d (S- and D-state) 4He-d-d, 3He-d-p, 3H-d-n and d-p-n. From the coupling constants we calculate the asymptotic normalization (spectroscopic factors) C21 of the corresponding cluster wave functions, which become: C20(6Li, αd) = 4.62 ± 0.23, C22(6Li, αd) = (1 ± 6) × 10?4, C20(α, dd) < 2, C20(3He, dp) = 3.5 ± 0.4, C20(3H, dn) = 2.6 ± 0.3 and C20(d, np) = 1.66 ± 0.1.  相似文献   

19.
By using different gauges, the relativistic rates for the Kαα2(1s?2→2s?12p12?1) and the Kα2h(1s?2→1s?12p12?1) transitions are calculated for Ne, Ar, Ca, Fe and Cu. The problem in the use of the single configuration HF model is discussed.  相似文献   

20.
Cross sections for 42P12?42P32 fine-structure mixing in potassium, induced in collisions with N2, H2, CO, and CH4, were determined by methods of atomic fluorescence spectroscopy. The experiments were carried out at a temperature of 342 K, a K density of 6 × 109 cm?3 and mtorr buffer gas pressures, and yielded the following cross sections Q1(42P12→42P32) and Q2(42P12→42P32 (in units of 10?6 cm2): for N2, 79 and 54; for H2, 57 and 39; for CO, 98 and 64; for CH4, 86 and 58. The values for N2 and H2 supersede those reported previously by McGillis and Krause (1968).  相似文献   

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