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1.
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   

2.
The predictions of perturbative QCD are derived in the deep euclidean region, whereas the physical region for most observables is timelike. The confrontation of these predictions with experiment thus necessitates an analytic continuation. This we find introduces large higher order corrections in terms of αs(|Q2|), the usual choice ofperturbative expansion parameter. These corrections are naturally absorbed by changing to the expansion parameter a(Q2) = |αs(Q2)|(Re αs(Q2)/|αs(Q2)|)(n?2)3, where αs(Q2)n is the leading term in the spacelike region. For the intermediate range of Q2 experimentally accessible at present, where a(Q2) is significantly smaller than αs(|Q2|), we find the resulting phenomenology is improved. In particular, we demonstrate how the values of ΛMS obtained from analyses of quarkonium decays become consistent.  相似文献   

3.
We argue that pion and nucleon structure functions differ principally due to their different numbers of quarks and different scales of confinement. The former generates an x rescaling while the latter, in QCD, gives rise to a Q2 rescaling. Together these lead to the relation
Fπ(x, Q2) = FN(23x, ξ NπQ2)
with ξNπ ? 0.16, for x values away from the end points. This relation is in good agreement with data.  相似文献   

4.
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   

5.
Given a mapping x → ?(λ,x), whose bifurcation points accumulate at λ = Λ, it is shown that the iterates (?α) [?2p?μ/δp, X+y/(?α)p)?X] converge to a function ψ(μ,y)asp→∞, where X maximizes ?(Λ∞,x). The function ψ is universal up to scaling in μ and y, and satisfies ψ(μ/δ,ψ(μ/δ,?y/α)) = ?α?1ψ(μ,y). This result generalizes the well-known Feigenbaum universal function g(y) with g(g(?y/α)) = ?g(y/α, which is the special case for μ = 0.  相似文献   

6.
The Coriolis interactions between ν1 and ν3, and between ν2 and ν3 in SO2 have been analyzed to obtain the signs of the products ζ3.1c(a?Q3)(b?Q1) and ζ3.2c(a?Q3)(b?Q2). It has been found that both of the signs of these products are positive. Then, relative signs of (?Q1) have been determined using the calculated values of the Coriolis zeta constants for the present definition of the normal coordinates. The obtained sign combination of (?Qi) is ±(+?+), which agrees with the one predicted by the molecular orbital calculations. Using the sign combination (+?+), the polar tensors of S and O atoms were also calculated.  相似文献   

7.
Nuclear spectroscopic quadrupole moments of the radioactive isotopes 131Cs, 132Cs, and 136Cs have been determined from the hyperfine structure of the 62P32 state by the level crossing method. The results including a Sternheimer correction are: Qs(131Cs) = ?0.625(6) b, Qs(132Cs) = +0.508(7) b, Qs(136Cs) = +0.225(10) b. The quadrupole moments of all the Cs isotopes from A = 131 to A = 137 are recalculated. It is shown, that nuclear quadrupole moments of a specific isotope obtained from different atomic P-states only agree within the limits of error after application of the Sternheimer correction. The increase of Qs with decreasing neutron number conforms with other observations and theoretical calculations stating that for elements around Z = 55 nuclear deformation develops below N = 82. The staggering of the sign of Qs may be interpreted as consequence of an oblate-prolate degeneracy of the nuclear energy surface. Some magnetic moments have been slightly improved: μI(132Cs) = 2.219(7) μN, μI(136Cs) = 3.705(15)μN (corrected for diamagnetism).  相似文献   

8.
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   

9.
For free and interacting Hamiltonians, H0 and H = H0 + V(r) acting in L2(R3, dx) with V(r) a radial potential satisfying certain technical conditions, and for ? a real function on R with ?′ > 0 except on a discrete set, we prove that the Moller wave operators
Ω± = strong limit eit?(H) e?it?(H0)
exist and are independent of ?. The scattering operator
S = (Ω+)1Ω?
is shown to be unitary. Our proof utilizes time independent methods (eigenfunction expansions) and is effective in cases not previously analyzed, e.g. V(r) = sinrr and many others.  相似文献   

10.
It is shown that the scaling law for partial-wave amplitudes Im fl(s) holds for lγ (√s/4μ) (α(4μ2)?1) log s, if the leading Regge singularity α(t) in the t-channel is bounded by
Re α(t) ? α(4μ2+α(4μ2)?1(t?2μ)
and is smooth near t = 4μ2 in the sense of eq. (4).  相似文献   

11.
The order α(Q2) correction to the particle multiplicity ratio in gluon and quark jets is calculated in QCD. We find
r=941?αCA13+N?3CA?2N?CF3C2A
with r=〈ngluon jet/〈nquark jet. The method used is systematic and could be used for an order α(Q2) calculation.  相似文献   

12.
The color bond structure of a quark-antiquark system is extended, in the long-range approximation, self-consistently to the baryonic three-quark bond structure for SU(3)c and generally to the N-quark bond structure for SU(N)c. The universal (N-independent) mass square eigenvalues for massless quarks are
M2=(HN)2?2mρ2α=13N?3να+constant, να=0,1,2,…
.  相似文献   

13.
The implications of the anomalous superconformal Ward identities for the construction of effective actions describing the low-energy dynamics of supersymmetry theories are investigated. The results apply to any N = 1 supersymmetry theory with an anomaly structure,
Dα?Vαα?+2DαS=0
, where Vαα? is the supercurrent and the chiral superfield S represents the anomaly.  相似文献   

14.
We calculate the effective electron-hole interaction Vre in the presence of an exciton gas, which reads in real space:
Vre(r)=?e2r{1+ i=14(?1)iCiexp(?Zira}
The parameters Ci and Zi are given explicitly for GaAs. For this material, we show the binding energy of the exciton is weakly modified so long as 8πR0?exa03kT?1. (R0, exciton Rydberg, a0 exciyon radius, ?ex exciton density, T temperature).  相似文献   

15.
We prove a theorem concerning the energies of the 2S and 3D states in a potential V(r) = ?g2r + Vc(r), where Vc is a non-singular confining potential. If (ddr)3(r2Vc) is positive, then the 3D state lies above the 2S state, provided
ddr1rddr2Vc+rdVcdr < 0, ?r>0.
For Vc = rα, this corresponds to 0 < α < 2.  相似文献   

16.
The rotational spectrum of methylene cyanide has been measured up to J = 62 and a total of 82 b-type transitions have been obtained. These data have been analyzed with a semirigid rotor Hamiltonian to give accurate rotational and centrifugal distortion constants. The rotational constants are (in MHz) A = 20882.7537 ≠ 0.017, B = 2942.3003. ≠ 0.0031, C = 2616.7225 ≠ 0.0031 The quartic centrifugal distortion constants are (in MHz)
ΔJ (1.855455 ≠ 0.014) x 10?3 ΔJK = (?6.79218 ≠ 0.027) x 10?2
ΔK (8.621628 ≠ 0.013) x 10?1 δJ = (4.892607 ≠ 0.016) x 10?4
δK = (6.7501 ≠ 0.29) x 10?3
The uncertainties are twice the standard deviations in the constants obtained from the least squares analysis, and represent approximately 95% confidence limits.  相似文献   

17.
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   

18.
The Stark effect of rotational and torsio-rotational transitions of propargyl mercaptan has been analyzed. Assuming a dependence of the dipole moment components on the internal rotation angle of the type: μa = μa0 + μa(1)cosα, μb = μb0 + μb(1)cosα, and μc = μc(1)sinα, the following values of the determinable quantities were obtained: μaeff = 0.718 ± 0.003 D, μbeff = 0.495 ± 0.010 D, and μc(1) = 0.809 ± 0.015 D.The SH bond moment was also evaluated from μc(1) and compared with the SH bond moment of similar molecules.  相似文献   

19.
The 0-0, 1-1, 2-2, and 3-3 bands of the A2Π-X2Σ+ transition of the tritiated beryllium monohydride molecule have been observed at 5000 Å in emission using a beryllium hollow-cathode discharge in a He + T2 mixture. The rotational analysis of these bands yields the following principal molecular constants.
A2Π:Be = 4.192 cm?1; re = 1.333 A?
X2Σ:Be = 4.142 cm?1; re = 1.341 A?
ωe′ ? ωe″ = 16.36 cm?1; ωe′Xe′ ? ωe″Xe″ = 0.84 cm?1
From the pure electronic energy difference (EΠ - EΣ)BeT = 20 037.91 ± 1.5 cm?1 and the corresponding previously known values for BeH and BeD, the following electronic isotope shifts are derived
ΔEei(BeH?BeT) = ?4.7 ≠ 1.5cm1, ΔEei(BeH?BeT) = ?1.8 ≠ 1.5cm1
and related to the theoretical approach given by Bunker to the problem of the breakdown of the Born-Oppenheimer approximation.  相似文献   

20.
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