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1.
John Lekner 《Physica A》1982,112(3):544-556
We derive comparison identities for waves satisfying the equation d2Ψ/dz2+q2(z)Ψ=0. One of these identities is used to show that to second order in the product (wavenumber component normal to interface) × (interface thickness), the reflection amplitude is given by r=(1?2q1q2l2)(q1?q2)(q1+q2), where l is a legnth determined by the deviation of the interface profile from a step, and q1, q2 are the normal components of the wave numbers in media 1 and 2 on either side of the interface. For the continuous interfaces discussed, l is about two-fifths of the 10–90 interface thickness. The corresponding formula for the transmission amplitude is t=(1+12(q1?q2)2l2)2q1(q1+q2).  相似文献   

2.
The (d, 3He) and (α, t) proton transfer reactions on 91Zr were studied at incident energies of 24.3 and 35.4 MeV, respectively. Angular distributions were measured from 6° to 50° (90Y) and 60° (92Nb). High detection efficiency and good energy resolution were obtained by using a magnetic spectrograph in connection with a multiwire proportional chamber. For the low-lying multiplet levels in both nuclei angular momentum transfers and spectroscopic factors were determined by DWBA analysis. In 92Nb the states at 0, 0.135, 0.29, 0.36 and the sum of the states at 0.48 and 0.50 MeV show typical l = 4 shapes. They belong to the (1g92π)(2d52ν) sextet. The corresponding multiplet in 90Y is weakly populated ( ≦ 20 μb/sr), and l = 4 shapes are found for the levels at 0.68, 0.78, 0.95, 1.05 and 1.30 MeV proving previous assignments. The members of the low-lying (2p12π)(2d52ν) doublets in 90Y and 92Nb exhibit a characteristic l = 1 angular shape. The levels at 1.42, 1.57, 1.64, 1.76 and 1.81 MeV in 90Y are excited both by l = 1 and l = 3 resulting from a strong mixing of the (2p32π)?1(2d52ν) and (1f52π)?1 (2d52ν) multiplets. Only the level at 2.03 MeV displays a pure l = 3 shape. From the spectroscopic information on the (2p12π)(2d52ν) and (1g92π)(2d52ν) multiplets in 90Y and 92Nb the g.s. configuration mixing in 91Zr is deduced.  相似文献   

3.
The g-factor of the [π(2p12)1v(2d52)1]2? state in92Nb(τ = 6.2 μsec) was determined by means of perturbed angular distribution methods using the 92Zr(p, n)92Nb reaction in a liquid alloy. The extracted v(d52) magnetic moment is discussed in terms of the core-polarization effect.  相似文献   

4.
At 57 MeV bombarding energy the (α, 2He) reaction has been investigated on targets of 54,56Fe, 58,60,62,64Ni, 64,66Zn, and 70Ge. Selective excitation of the 2n configurations (f52g92)7?, (g92) 8+2, and (g922d52)6+ was observed in all final nuclei. A linear A and T dependence of the binding energies of these states was observed. This systematic behaviour is well described by the Bansal-French model. The values obtained for the strength of the isoscalar and the isovector parts of the particle-hole interaction are consistent with the average of the values describing the corresponding single-particle states.  相似文献   

5.
Oscillator strengths for 11S?n1P transitions for some members of the helium isoelectronic sequence have been calculated by utilizing the dipole length, velocity and acceleration forms of the transition matrix element with coupled H.F. wave functions. Good agreement has been obtained between the values of the oscillator strengths. The quantities (?A??L) and (?A??V) decrease slowly with nuclear charge Z, whereas (?L-?V) first increase to a maximum value and then decreases slowly.  相似文献   

6.
The q2 variation of the factor ?+(q2) in the decay K+π0e+ν has been studied using a sample of even detected in the CERN 1.1 m3 heavy-liquid bubble chamber. The data are consistent with a linear development ?+(q2)=?+(0) (1+λ+q/m2π) with λ+=0.027±0.008.  相似文献   

7.
The deep inelastic structure function D(ω, q2) is calculated in the leading log approximation for (2π22S (q02) 1n ω < 0.84 1n(1αS(q2)). For larger ω up to (2π22S) 1n ω < 0.42 α2S (q02)α2S(q2) the influence of reggeon cuts proves to slow down the growth of the structure function. A reggeon diagram technique is developed, and D is calculated up to a pre-exponent O(1), leading to D(ω, q2) ∝ q2 for (2π22S(q20) 1n ω ? 0.42 α 2S(q02)αS2(q2). By assuming the reggeon diagrams when ω is still greater, one can expect to obtain a strong coupling behaviour: D(ω, q2) ∝ q2(ln ω)η (η <2).  相似文献   

8.
No perturbation between two valence states of NO has ever been identified, although many valence-Rydberg and several Rydberg-Rydberg perturbations have been extensively studied. The first valence-valence crossing to be experimentally documented for NO is reported here and occurs between the 15N18O B2Π (v = 18) and B2Δ (v = 1) levels. No level shifts larger than the detection limit of 0.1 cm?1 are observed at the crossings near J = 6.5 [B 2Π(F1) ~ B′ 2Δ(F2)] and J = 12.5 [B 2Π(F1) ~ B′ 2Δ(F1)]; two crossings involving higher rotational levels could not be examined. Semi-empirical calculations of spin-orbit and Coriolis perturbation matrix elements indicate that although the electronic part of the B 2Π ~ B′ 2Δ interaction is large, a small vibrational factor renders the 15N18O B (v = 18) ? B′ (v = 1) perturbation unobservable. Semi-empirical estimates are given for all perturbation matrix elements of the operators Σia?ili·si and B(L±S? ? J±L?) which connect states belonging to the configurations (σ2p)2(π2p)412p), (σ2p)(π2p)412p)2, and (σ2p)2(π2p)312p)2.  相似文献   

9.
In this note we determine the oscillator strengths for the dipole absorption of neutral bound excitons in direct gap semiconductors, using our previously obtained 35-term Page and Fraser type wave function, and taking into account the detailed electronic structure as well as the electron-hole exchange interaction.The envelope part of the oscillator strengths varies considerably with the electron-hole mass ratio σ = m1em1h, and is maximum for the (D0, X)- complex when σ = 0.4. For typical σ-values (σ? 0.1–0.2), ?(D0,X) ? 10?(A0,X). But when σ approaches zero, the overlapping of the electron and the hole envelope wave functions of the (A0,X)-complex decreases progressively so that the oscillator strength also decreases and tends to zero.In the case of zinc-blende materials (Td) and positive spin-orbit coupling at k = 0, we confirm that the line strength for transitions to or from J = 126) or J = 527 + Γ8) level of the (A0, X)-complex is equal to one quarter of the line strength to or from the J = 328) level.In the case of CdS, where our computed values are only in qualitative agreement with the experimental values, we discuss the use of the phenomenological result of Rashba.  相似文献   

10.
The vibration-rotation transitions for v = 1 ← 0 of NO (2Π12) have been studied by using the technique of laser magnetic resonance spectroscopy. Five magnetic resonance lines are observed with three CO laser lines in the range from 1859 to 1886 cm?1. From these, three zero-field transition frequencies, v = 1 ← 0; R(32), P(72), and P(92) are obtained with an accuracy of ±0.0007 cm?1. The molecular constants which have been determined by borrowing centrifugal constants from a previous infrared work are B021 = 1.72004 ± 0.00006 cm?1, B121 = 1.70212 ± 0.00010 cm?1, and G(v = 1) ? G(v = 0) (for 2Π12) = 1875.8470 ± 0.0007 cm?1.  相似文献   

11.
The vibrational modes localized at the interface between two distinct crystals have been studied for a simple crystal model obeying all of the invariance conditions required for models used in studies of dynamical properties of crystal surfaces, and giving rise to Rayleigh surface waves. The two crystals are assumed to be semi-infinite simple cubic and to have the same lattice parameter a. They differ by their mass (M and MA) and the central force interactions between first (K and Ka) and second nearest neighbors 12K and 12KA. The interface is obtained by coupling the (001) free surfaces of these distinct crystals by central force intractions (K'). We find that the variation of the interaction conditions (K') at the interface and of the (KM)(KAMA) parameter has the following qualitative effects on the properties of surface and bulk phonons. When (K') increases from zero to a finite value, the frequencies of the surface phonons increase and are splitted in the case of two identical crystals. One can say that the surface phonons are transformed into interface modes. For some values of K'K and (KM)(KAMA) parameters these interface phonons may be admixed with bulk phonons and thus become virtual interface states.  相似文献   

12.
Using a target prepared by on-line isotope separation, thermal neutron capture in 84Rb (Iπ = 2?) has been shown to induce proton emission to the ground state (0+) and first excited state (2+) of 84Kr. The branching ratio was measured as Γp(0+)Γp(2+) = 4.7 ± 0.7, favouring a 32? assignment of the capturing state without excluding 52?, and the (nth, p) cross section as 12 ± 2 b. The energy available for the process was determined to be 3.45 ± 0.01 MeV, in agreement with other mass data in the region.  相似文献   

13.
The helicity, h?, of μ? in π-decay has been determined as positive (h??+0.90) from the average polarization, Pav≡〈JB·sμ〉, of 12B produced in the μ?+12C→νμ+12B reaction. We obtain also dynamical information on μ-capture: (i) the weak magnetism form factor, μ=4.5±1.1, and (ii) the sum of the induced pseudoscalar (gp) and the 2nd class induced tensor (gT) couplings versus gA, (gP+gT)gA=7.1±2.7. The latter result, adopting the “canonical” value of gPgA, leads to gTgA=+1±2.7 which is compatible with zero and in strong contradiction with the value ?—6 recently advocated by Kubodera, Delorme and Rho.  相似文献   

14.
Discharges through mixtures of helium and neon show two band groups near 4250 and 4100 Å as first observed by Druyvesteyn. These bands, assigned to the HeNe+ ion by Tanaka, Yoshino, and Freeman, have been studied under high resolution and have been fairly completely analyzed. The upper state of the transition is a very weakly bound state resulting from He+(2S) + Ne(1S0). There are two lower states resulting from the two components of Ne+(2P) + He(1S0). The upper of these two (2Π12) is also very weakly bound while the lower of the two, the 2Σ+ ground state, has a dissociation energy of 0.69 eV and an re value of 1.30 Å. All bands in both band groups show four branches designated Rff, Qef, Qfe, and Pee. From their analysis the rotational constants in the various vibrational levels of the three electronic states have been determined. While no spin splitting in the B2Σ+ state has been found the ground state X2Σ shows a very large spin splitting and the A22Π12 state a very large Ω-type doubling. The vibrational numberings in all these states were established by the study of the spectrum of 3HeNe+. At the same time the hyperfine structure observed in all lines of 3HeNe+ confirmed the nature of the upper state B2Σ+ as resulting from He+ + Ne, i.e., by charge exchange from the ground state. The 2Π12 component of the 2Π state has not been observed, presumably because of low intensity.  相似文献   

15.
Dependence of static dielectric susceptibility and correlation length of charge density waves (CDW) with weak defects on parameter of incommensurability with lattice is investigated. In almost commensurate phase (h?hchc), χ ~ (h?hc)13 In-43 hc/h?hc and Rc ~ (h ? hc)23. In13 hc/h ? hc. Far from commensurability (h?hc) χ~ (a+h2c/h2)-23, Rc ~ (a + h2c/h2)-23, where a is the dimensionless ratio of random potential intensities, corresponding to backward and forward scattering impurities.  相似文献   

16.
Amorphous Fe40Ni40B20 (VITROVAC 0040) alloy has been investigated using 57Fe Mössbauer Spectroscopy. The Curie temperature Tc is found to be well defined and is 695 ± 1 K. The quadrupole splitting just above Tc is 0.64 mm sec?1. The crystallization temperature is 698 ± 2 K, close to but definitely above Tc. The average hyperfine field Heff(T) of the glassy state shows a temperature dependence of Heff(0)[1 ? B32(T/Tc)32 ? C52(T/Tc)52 ? …] indicative of the existence of spin wave excitations. The values of B32 and C52 are found to be 0.40 and 0.06, respectively, for T/Tc ? 0.72. At temperatures close to Tc, Heff(T) varies as (1 ? T/Tc)β where β is one of the critical exponents and its value is found to be 0.29 ± 0.02.  相似文献   

17.
The quadrupole coupling constant (eQVzzh) of the 8? 606 keV level of 112In has been measured by the DPAD method in the hexagonal lattice of metallic cadmium. The quadrupole moment of the level is deduced to be |Q| = 0.093(6) in agreement with the theoretical value for the configuration [π(g92)?1 ν(h112)112n]8?.  相似文献   

18.
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   

19.
Lifetime and g-factor measurements have been made with pulsed beam-γ time-differential techniques using the 89Y(α, 2n)91Nb and 88Sr(α, n)91Zr reactions. A mean lifetime τ = 14.4 ± 0.5 nsec and a g-factor of 1.26 ± 0.04 were obtained for the 132? 1985 keV level in 91Nb and τ = 41.9 ± 1.2 nsec and g = 0.70 ± 0.01 were obtained for the 152? 2288 keV level in 91Zr. These results are compared to theoretical calculations for g92)2p12) and g92)(πp12)(vd52) configurations in 91Nb and 91Zr, respectively.  相似文献   

20.
Differential cross sections for 87Sr(d, t)86Sr transitions to the (1g92)?2 states of 86Sr were obtained with the Pittsburgh 18 MeV deuteron beam and the Enge split-pole spectrograph. States of 86Sr up to 3.82 MeV in excitation were studied with a total resolution of 12 keV. Successful distorted-wave Born approximation (DWBA) predictions for 87Sr(d, t) 86Sr angular distributions permitted the extraction of l-values and spectroscopic strengths. The sum-rule value agrees with the observed value for the (1g92)?2 configuration. The observed g92 strength is spread over 13 states. Contrary to an earlier interpretation, the 0+ ground state is found to contain only 65% of the (g92)20+ strength. Similarly, the full 4+ strength is not located in a single state. The new data change the interpretation of the (g92)?2 spectrum of 86Sr. They significantly alter the deduced low-spin matrix elements and bring them into much closer agreement with those derived from 88Y. Several new negative-parity states dominated by l = 1 orbital angular momentum transfer have also been identified.  相似文献   

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