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1.
A marked difference of experimental analyzing powers A (θ) for208Pb(p, t)206Pb (0g+and 02+) reaction is explained by considering sequential transfer as wesses as well as the one-step process. The calculated A(0θ) for the 02+ state is very sensitive to the wave functions employed. An enhancement of the cross sections for the ground-state transitions of three Pb isotopes is found to be due to sequential transfer processes.  相似文献   

2.
Using an extended AKNS-ZS formalism developed in earlier work, we present a systematic inverse spectral transform analysis and solution of the generalized nonlinear Schrödinger equation
iqt+(fq)xx+2fq\q\2+2q∫?∞xfx|q|2dx=0
which arises in certain physical problems involving inhomogeneous interactions (or media). Physically interesting forms of the inhomogeneity function f(x) are discussed, that support localized solutions and permit non-dissipative tunneling of lump-like solutions through the inhomogeneity.  相似文献   

3.
The opportunity to test a new equation for the computation of the lattice energy and at the same time examine a disparity in the literature data for the enthalpy of formation of the azide ion, ΔHθ?(N3?) (g) was the motivation for this study. The results confirm our earlier calculation and show the new equation to be reliable. Thermodynamic data produced in the study take values: ΔHθ?(N3?)(g) = 144kJ mor?1ΔHθhyd(N3?) = ?315 KJ mol?1 or ΔHθhyd(N3?) = ?295 KJ mol?1UPOT(NaN3) = 732 kJ mol?1UPOT(KN3) = 659 kJ mol?1UPOT(RbN3) = 637 kJ mol?1UPOT(CsN3) = 612 kJ mol?1UPOT(TIN3) = 689 kJ mol?1. The lattice energies of azides whose enthalpies of formation are documented have been calculated as well as the enthalpy of formation of the azide radical.  相似文献   

4.
5.
In lattice gauge theory, many computations such as the strong coupling expansions, mean field theory, or the few plaquette models require the evaluation of the one-link integral in the presence of an arbitrary N × N complex matrix source (J). For SU(N) gauge theories, we express our general solution to the external field problem as an integral over the maximal abelian subgroup [U(1)]N?1
dUe?r(J+U+U+J)=∫i=1Ndøp(Σøi)eS0+InG
where S0 = 2Σkzk cos(φk ? θ), zj are eigenvalues of √JJ+, e2iNθ=detJ/detJ+, and G is an appropriate jacobian determinant. Our explicit solution follows from differential Schwinger-Dyson equations cast in a separable form by using fermionic variables, and the special cases of N = 2, 3 and ∞ agree with earlier derivations.  相似文献   

6.
The transverse spin pair correlation function pxn=<SxmSxm+n>=<SxmSxm+n> is calculated exactly in the thermodynamic limit of the system described by the one-dimensional, isotropic, spin-12, XY Hamiltonian
H=?2Jl=1N(SxlSxl+1+SylSyl+1)
. It is found that at absolute zero temperature (T = 0), the correlation function ρxn for n ≥ 0 is given by
ρx2p=142π2pΠj=1p?14j24j2?12p?2jif n=2p
,
ρx2p+1142π2p+1Πj=1p4j24j2?12p+2jif n=2p+1
, where the plus sign applies when J is positive and the minus sign applies when J is negative. From these the asymptotic behavior as n → ∞ of |?xn| at T = 0 is derived to be xn| ~ an with a = 0.147088?. For finite temperatures, ρxn is calculated numerically. By using the results for ?xn, the transverse inverse correlation length and the wavenumber dependent transverse spin pair correlation function are also calculated exactly.  相似文献   

7.
The microwave spectrum of MnO3F has been remeasured and several corrections and new results have been obtained: B0 = 4129.141 MHz, DJ = 1.12 kHz, DJK = 1.87 kHz; α3B = 8.622, α5B = ? 11.994, α6B = 6.042, |q5| = 16.005, and |q6| = 8.456 MHz.  相似文献   

8.
The fine structures of the (ν1 + ν2) and (ν2 + ν3) combination bands of ozone in the 5.7-μm region have been recorded and analyzed. The two vibrational states are coupled through Coriolis and second-order distortion terms. The interaction has been treated by the numerical diagonalization of the secular determinant for the two coupled states. With the centrifugal distortion parameters fixed to the ground state values, the following constants have been obtained: ν1 + ν2 = 1796.266, A110 = 3.6104, B110 = 0.44145, C1110 = 0.39029, ν2 + ν3 = 1726.526, A011 = 3.5537, B011 = 0.43982, C1011 = 0.38844, Y13 = ?0.466, and X13 = ?0.010 cm?1. In addition, the following anharmonic constants have been obtained: x12 = ?7.821 and x23 = ?16.494 cm?1. The value of the dipole moment ratio, R = 〈011|μz|0〉〈110|μx|0〉, is 1.30 ± 0.10.  相似文献   

9.
We show that the long time behaviour of the velocity correlation function in a two-dimensional classical system with pairwise repulsive potentials can be represented by a series expansion of the form
〈υ1xυ1x(t)〉 = d0t?1 + d1t?1log t/t0 + d2t?1(log t/t0)2 + …
, where t0 is mean free time between collisions. To lowest order in the density an exact expression has been obtained for d1 employing the kinetic theory ofsystems with hard-core interactions. The significance of the series is discussed at low and intermediate densities.  相似文献   

10.
Angular distributions of six polarization transfer coefficients Kxx′(θ), kxz′(θ), Kzx?(θ), Kzz?(θ), and Kyyy?(θ); of the four analyzing powers Ay(θ), Axx(θ), Ayy(θ), and Azz(θ); and of the polarization function Pý(θ), have been measured atEd = 10.00 MeV for the reaction 2H(d, n)3He. Measurements were made for neutron lab angles between 0° and 80° in 10° steps. Additionally the y-axis associated quantities were measured at θ1ab = 99°. Most of the measured coefficients are large at some angles and all show considerable variation with angle.  相似文献   

11.
The Casimir energy is evaluated for a free scalar field that has a mass term m2(x1), depending on one space coordinate x1. The formalism for evaluating the Casimir energy is developed for the case of m2(x1) finite everywhere in d-dimensional space-time. The case with m2(x1) = m02θ(12L-|x1|) + m2θ (|x1| - 12L) is explicity evaaluated for any value of 1197 1568 V m0 and m without any approximation. The result consists of valume energy terms, a surface term, and a non-leading term. Most of the UV divergences are in the volume energy terms and renormalize the coupling constants of the underlying theory. The surface energy term is finite for d ? 4 and divergent for d ? 5 due to the boundaries being sharp. A closed finite expression is obtained for the non-leading term. Our results are shown to reproduce the known Casimir energies for the limiting cases, 1197 15 m0 → ∞ andm → ∞.  相似文献   

12.
This is a perturbative analysis of the eigenvalues and eigenfunctions of Schrödinger operators of the form ?Δ + A + λV, defined on the Hilbert space L2(Rn), where Δ = Σi=1n?2?Xi2, A is a potential function and V is a positive perturbative potential function which diverges at some finite point, conventionally the origin. λ is a small real or complex parameter. The emphasis is on one-dimensional or separable problems, and in particular the typical example is the “spiked harmonic oscillator” Hamiltonian, ?d2dx2 + x2 + l(l + 1)x2 + λ|x|, where α is a positive constant. When this kind of perturbation is very singular, the first-order Rayleigh-Schrödinger perturbative correction, (u0, Vu0), where u0 is the unperturbed eigenfunction, diverges. This analysis constructs explicitly calculable terms in a modified perturbation series to a finite order, by using linear operator theory in concert with approximation methods for differential equations. Along the way a connection between a W-K-B type approximation and Bessel functions is exploited.  相似文献   

13.
Emission spectra for the electronic transitions 6–17pπ 3Πg-2s a3Σu+ and 7–16pσ 3Σg+-2s a3Σu+ of He2 are reported and the electronic structures of npπ 3Πg? and np(2Σg+, 3Πg+) characterized. The energy levels associated with (1σg)2(1σu)np(3Σu+, 3Πg+) exhibit extensive channel mixing, which leads to a breakdown of conventional band models for the higher n1-members of these Rydberg “series.” However, a model based on multichannel quantum defect theory quantitatively correlates the observed level structures. The higher-energy (n1 > ~5) portions of the np(3Σg+,3Πg+) channels can be represented by two eigen-quantum defects μ1 = 0.225 and μ2 = 0.930 and the close- to loose-coupling matrix elements U11 = U22 = [N(2N + 1)?1]12 and U12 = ?U21 = [(N + 1)(2N + 1)?1]12. The inclusion of energy dependence in the μα's leads to quantitative correlations for all n1-values.  相似文献   

14.
From a study of (p,t) reactions on 31P and 30Si it is suggested that in 29P the states with Jπ=121+ and 122+, the pair 322+, 521+, and the pair 723+, 921+ are related by weak coupling of a s12 proton with the states 01+, 02+, 21+ and 41+ respectively of 28Si. Completely atypical L = 2 angular distributions have been obtained for the 321+ and 522+ states in 29P and it is suggested that this is due to contribution by two-step processes.  相似文献   

15.
Two electrochemical methods - involving the application of a long-time galvanostatic current pulse and a small potentiostatic voltage step to a M/MxSSE cell - are presented. From the overvoltage, respectively current response the chemical diffusion coefficient (DM+) and the thermodynamic factor (? ln a/? ln c) are obtained. The methods have been applied to the cells: Li/1M·LiClO4 in propylenecarbonate/LixTi1.03S2 0.05 < x < 0.95, T = 20°C; and LixCoO2 0.10 < × < 1, T = 20°C. From the application of the current pulse/voltage decay method it followed: DLi+(LixTi1.03S2) = 1?4 × 10?8cm2s?1, with a slight tendency to increase with decreasing x; DLiC(LixCoO2) = 2?40 × 10?9cm2s?1, decreasing with decreasing x. These values are among the highest found for solid state Li+-ion diffusion, and will be closely evaluated and compared with data reported by other workers. The x-dependence of the thermodynamic factor, determined from kinetic data, for LixTi1.03S2 (x = 0.05-0.95) and LixCoO2 (x = 0.60-1.00) is in accordance with a simple thermodynamic model. Unlike for LixTi1.03S2, the thermodynamic factor for LixCoO2, determined from the EMF-x relation, cannot be accounted for by this model. Furthermore, a fast, but crude method to determine the average chemical diffusion coefficient in LixTi1.03S2 and LixCoO2 is discussed.  相似文献   

16.
Quark masses     
In quark gluon theory with very small bare masses, -ψMψ, spontaneous breakdown of chiral symmetry generates sizable masses Mu, Md, Ms, … We find (Mu + Md) /2 ≈ mp/ √6 ≈ 312 MeV, and Ms ≈ 432 MeV. Scalar densities have well determined non-zero vaccum expectations 〈0|ua|0〉 ≡ 〈0|ψ(x) (λa/2)ψ(x)/0〉 ≈ ?π2Ma, i.e〈0? uo/vb0〉 ≈ 8 × 10?3 (GeV)3 at an SU(3) breaking of the vacuum c′ ≡ 〈0|u8|〉/〈0|uo|0〉 ≈ ? 16%  相似文献   

17.
Within the framework of a perturbation theory and a quasicrystalline approximation we have solved the linearized equation of motion for the circular spin component S+j = Sxj + iSyj in a one-dimensional amorphous ferromagnet with periodic external excitation of the spin S+0 at site j = 0. It is shown that localized spin modes of the simple form «S+ja? = S + (q0) exp[iq0 · Rj - iω(q0) t] exp (-gk?Rj?) with fall-off-length κ-1 are solutions of the ensemble-averaged equation of motion. On the other hand, we have a damping of extended spin waves according to exp(-Γt). A simple relation is derived between the fall-off-length κ-1 of localized spin modes and the damping factor Γ of extended spin waves. Analogous results hold for phonons in amorphous materials.  相似文献   

18.
Predissociations in the y1Πg and x1Σg? Rydberg states of N2 (configurations u?14pσ and u?13pπ, respectively) and their likely causes, are discussed. Peaking of rotational intensity at unusually low J values, without sharp breaking off, is interpreted as due to case c? or case ci predissociation. Λ doubling in the y state, attributed to interactions with the x1Σg? state and with another, 1Σ+, state of the same electron configuration as x, is analyzed. From this analysis the location of the (unobserved) 1Σg+ state, here labeled x′, is obtained. It is concluded that the predissociation in the Π+ levels of the y state is an indirect one mediated by the interaction with x′ coupled with predissociation of x′ by a 3Σg? state dissociating to 4S + 2P atoms: combined, however, with perturbation of the y state by the k1Πg Rydberg state (configuration g?14dπ), whose Π+ levels are completely predissociated.  相似文献   

19.
Excitation functions at θ = 90° have been measured for 16O(3He, γ0?2, 3?5, 6)19Ne, 15N(3He, γ0, 1?4)18F, 14N(3He, γ0, 1,2,3)17F, and 20Ne(3He, γ0 + 1)23Mg, in the range E3He = 3–19 MeV. The first reaction has also been studied at θ = 40°. Excitation functions at 90° have also been measured for 40Ca(3He, γ0?2)43Ti for E3He = 4–17 MeV and 4He(3He, γ0 + 1)7Be for E3He = 19–26 MeV. Angular distributions have been measured for the first four reactions.For the most excitation functions, a broad peak is observed, several MeV wide, centred at about Ex≈ 20 MeV. Superimposed on this, in some cases, are narrower peaks, with width ≈ 1 MeV. Energies and widths have been extracted for all resonances.Cluster-model calculations have been carried out, using methods similar to those which have proved successful for low-lying states in A= 18–19 nuclei. No satisfactory correspondence with the present results was found. The shell model has been used to calculate Γ3He and Γγ for 1?ω excitations in the final nuclei. These generally show good agreement with the trends of the experimental data. The results are consistent with the excitation of the giant dipole resonance in 3He capture, but much more weakly than in proton capture.  相似文献   

20.
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the 4d(3Σu+, 3Πu, 3Δu) → 2pπ3Πg, 4d(1Σu+, 1Πu, 1Δu) → 2pπ1Πg, 4s3Σu+ → 2pπ3Πg and 4s1Σu+ → 2pπ1Πg transitions analyzed. The 4dδj3Δu, 4dπj3Πu, 4dσj3Σu+ and 4sh3Σu+ states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, 4dσJ1Σu+, and 4sH1Σu+ states for v = 0. The term levels for these perturbed and l-uncoupled states have been confirmed (a) by analyses of bands with common levels from Δv = 0, ±1 sequences and (b) by analyses of the transitions between the above states from 4d and 4s and the c3Σg+ and C1Σg+ states associated with 3. Molecular constants are reported which have been partially corrected for the effects of l-uncoupling and the homogeneous perturbations between the state pairs J, H and j, h.  相似文献   

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