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1.
Using a recent theoretical method, the ratio of nuclear matrix elements was determined to be either 20.50+0.35?0.55 or 25.22+0.28?0.17 in the second-forbidden nonunique decay of 8 × 104 y 59Ni. These values of R were obtained from a value of L3/K = 0.008 ± 0.002 found by subtracting the theoretical ratio = 0.113 (based on QPEC = 1070 ± 8 keV) from the total ratio L/K = 0.121 ± 0.002, which was measured with a reactor-produced, doubly-mass-separated 59Ni source introduced as gaseous nickel-ocene, (C5H5)2, into a wall-less, anticoincidence, multiwire proportional counter. The 854–1008 eV L and the 8.33 keV K peaks were measured simultaneously. 相似文献
2.
Microwave spectrum of cis, trans-divinyl ether has been remeasured and doublet splittings were observed in most of the b and c type lines and also in a few of the a type transitions. The splittings were analyzed in terms of tunneling motion of the two vinyl groups through the planar configuration in which a steep potential barrier exists due to the repulsion between the α and β hydrogen atoms of trans and cis vinyl groups, respectively. An effective Hamiltonian the form was used for the analysis where terms in parenthesis apply only for the upper levels of the tunneling doublet. The values of Ga = 2.764, αv = ?0.391, βv = ?0.0067, and γv = +0.00065 (all in MHz) were derived in addition to the tunneling doubling Δv as 27.28 MHz and the refined rotational and centrifugal distortion constants. The potential barrier was approximated by a Gaussian function of the form and its height, A, was estimated to be 580 cm?1 (1.6 kcal/mole) by way of WKB approximation.The definitions of large-amplitude vibrations in non-planar and non-linear molecules were discussed and a criterion to distinguish internal rotation, pseudo-rotation, inversion, and puckering from each other was derived. The motion reported in this paper was classified as internal rotation by this criterion. 相似文献
3.
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), and Rc ~ (h ? hc). In. Far from commensurability , , where a is the dimensionless ratio of random potential intensities, corresponding to backward and forward scattering impurities. 相似文献
4.
The average multiplicity in deep inelastic electro- and neutrinoproduction at large ω(ω~s/Q2 + 1) is related in Feynman's version of the parton model to the average multiplicities in high-energy electron-positron annihilation and hadron-hadron scattering. The relation is: , where Ce+e? and Ch are, respectively, the coefficients of ln(s/M1⊥2) in the multiplicities from e+-e? and P-P in to hadrons, and M1⊥ is an average transverse mass. 相似文献
5.
R.F. Curl 《Journal of Molecular Spectroscopy》1973,48(1):165-173
The and transitions of the J = 7 levels of the ground state of CH4 have been observed by infrared-radio frequency double resonance using the 3.39 μ HeNe laser line. The transition frequencies are 423.02 ± 0.02 MHz and 1246.55 ± 0.02 MHz, respectively. Using these frequencies and the splitting of the E and F2 levels of the J = 2 state calculated from the molecular beam magnetic resonance spectra of Ozier, the centrifugal distortion constants are derived to be Dt = 132933 ± 10 Hz, H4t = ? 16.65 ± 0.2 Hz, and H6t = 10 ± 1 Hz. The J = 15 E(1) → E(2) microwave transition is predicted as 14150 ± 9 MHz. 相似文献
6.
The theory of the symmetry properties of the rotational and torsional levels is developed for molecules consisting of two identical XY2 groups connected by a symmetrical linear chain of atoms, with an arbitrary barrier to internal rotation. The levels are classified according to the representations of the double group of the Longuet-Higgins permutation-inversion group, and selection rules for electric dipole transitions are derived. It is shown that the symmetries of the normal coordinates of ethylene-like molecules can be different from those given recently by Papou?ek, Sarka, ?pirko and Jordanov. The results are applicable to the vibrational spectra of molecules like B2F4 and B2Cl4, which have low barriers to internal rotation in their ground states, and to the vibrational and rotational structure of electronic transitions of C2H4, where the combining electronic states may have very different torsional potential functions. 相似文献
7.
The magnetic phase diagram of FeCl2 · 2H2O has been determined by means of single crystal neutron diffraction experiments. Isothermal and isobaric measurements reveal the existence of first order and second order phase transitions separated by tricritical points at . Considerable hysteresis effects were observed at the antiferro—ferrimagnetic phase boundary at temperatures t < 0.33. 相似文献
8.
The magnetic hyperfine splitting vM=|gμNBHF/h| of 196mAu (jπ=12?; configuration ¦(π(; as dilute impurity in Ni has been determined with nuclear magnetic resonance on oriented nuclei as 96.0(2) MHz. With the known hyperfine field BHF = ?264.4(3.9) kG corrected for hyperfine anomalies the g-factor and magnetic moment of 196mAu are deduced to be |g| = 0.476(7) and |μ| = 5.72(8) μN. Taking into account the known magnetic properties of and isomeric states in the neighbouring odd Pt, Au and Hg nuclei the structure of the 12? state is discussed. 相似文献
9.
Experimentally, it is much easier to measure structure functions at fixed hadron energy Eh, rather than at fixed Q2. We prove the sum rules , Here s = 2mpEh and F2,3 are the standard functions for scattering of neutrinos on an isoscalar target. K is an unknown constant, and the corrections to the sum rules are O(αs2), O(αs1.75), respectively. 相似文献
10.
L.E. Brus 《Journal of Molecular Spectroscopy》1979,75(2):245-250
Previously unobserved acetylene fluorescence occurs following 1933-Å ArF laser excitation of C2H2 or C2H4 and their deuterated analogs in solid Ne and Ar hosts at 4.2 K. Acetylene is a photolysis product of matrix-isolated ethylene. Ground-state vibrational levels as high as ν″3 = 30 of the degenerate ν3 bending vibration are observed for C2D2. Only ν3 is appreciably active in the fluorescence. The negative ν3 anharmonicity, previously observed in the gas phase, also occurs in Ne host. Consideration of rotational selection rules indicates that the Ne host strongly hinders free rotation about the low-moment-of-inertia axis in the excited state. 相似文献
11.
Robert W. Field Richard A. Gottscho E. Miescher 《Journal of Molecular Spectroscopy》1975,58(3):394-413
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 B′2Δ (v = 1) levels. No level shifts larger than the detection limit of 0.1 cm?1 are observed at the crossings near and ; 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 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 and which connect states belonging to the configurations , , and . 相似文献
12.
The emission spectrum of the He2 molecule has been rephotographed in the ~4000–~5700 Å region and the , , and transitions analyzed. The 4dδj3Δu, 4dπj3Πu, and states have been characterized through v = 2 and the 4dδJ1Δu, 4dπJ1Πu, , and 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 and states associated with 3pσ. 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
13.
It is shown that magnetoconductivity in the critical region near the metal-insulator transition is equal to and the coefficient Al does not depend on the proximity to the mobility edge. The magnetic field leads to the mobility edge shift, which is proportional to , where v is the conductivity critical index. 相似文献
14.
A.H. Mueller 《Nuclear Physics B》1984,241(1):141-154
The order correction to the particle multiplicity ratio in gluon and quark jets is calculated in QCD. We find with r=〈n〉gluon jet/〈n〉quark jet. The method used is systematic and could be used for an order α(Q2) calculation. 相似文献
15.
G. Sobotta 《Solid State Communications》1982,43(11):875-877
A field theoretical model is proposed to describe the critical behaviour of a strongly inhomogeneous spin system with a position dependent concentration of magnetic atoms C(R) and magnetisation M(R). Assuming a finite number of Fouriermodes ,..., , to express C(R), the quenched randomness requires to interpret {} on a set of invariant or marginal lengths. As consequence, M(R) can be described by n Fourier-modes MQv, where . For short range spin-spin interaction, we find for strong inhomogeneity, i.e. large n, the critical exponent between those of the related homogeneous system and those of the spherical model. 相似文献
16.
A theoretical model used to describe the and B3Πg states of N2 is presented. Using recently acquired high resolution spectra of the (0-0) band, rotational energy levels of the v = 0 vibrational levels of these two states are generated with this model. These levels are in excellent agreement with those obtained using a combination differences technique. The precision of the model generated levels is 0.01 cm?1. The previously unpublished rotational levels of Dieke and Heath for the , B3Πg and C3Πu states are referenced to the (v = 0, J = 0) ground level and tabulated here. Estimates of the precision of their work are made. 相似文献
17.
T. Odagaki 《Solid State Communications》1980,33(8):861-865
A probability distribution for the off-diagonal matrix elements vnm of the tight binding Hamiltonian is assumed to be for and P(vnm = 0 otherwise. A homomorphic cluster CPA with the L(E) criterion is used to study localisation in a simple cubic lattice and a computer simulation is used to study a square lattice with the participation-ratio criterion. It is found, in both cases, that Anderson's transition takes place for a critical degree of disorder. 相似文献
18.
Two band groups near 1450 Å, first observed by Tanaka, Yoshino, and Freeman (J. Chem. Phys.62, 4484–4496 (1975)) in discharges through mixtures of helium and argon and assigned by them to the HeAr+ ion, were studied under high resolution. Like the similar spectrum of HeNe+ previously investigated, the spectrum of HeAr+ is a charge transfer spectrum. The upper state B2Σ+ of both band groups is derived from while the two lower states and X2Σ+ are derived from . All three states are very weakly bound, the two lower states even more weakly than the upper state. Unlike HeNe+ most of the HeAr+ bands are violet shaded. In the longward band group each band shows only three branches while in the shortward group there are four. The former observation shows that the state behaves like a 2Σ? state with γv ≈ 0. The B, D, γ, p, and ΔG values of all states were evaluated. While the Bv values of upper and lower states are nearly equal, the Dv values are quite different and this difference accounts for the violet shading of most of the bands even when B′v is slightly smaller than B″v; it also accounts for some of the extraheads and linelike features in the rotational structure. As in HeNe+ the component of 2Π was not observed. 相似文献
19.
John Miles 《Physica D: Nonlinear Phenomena》1984,11(3):309-323
The weakly nonlinear, resonant response of a damped, spherical pendulum (length l, damping ratio δ, natural frequency ω0) to the planar displacement εl cos ωt (ε ? 1) of its point of suspension is examined in a four-dimensional phase space in which the coordinates are slowly varying amplitudes of a sinusoidal motion. The loci of equilibrium points and the corresponding bifurcation points in this space are determined. The control parameters are and . If α < 0.441 there is a finite interval of v within which no stable equilibrium points exist. As v decreases through the upper bound (a Hopf-bifurcation point) of this interval the motion in the phase space becomes periodic and then, following a period-doubling cascade, chaotic. There may be alternating sub-intervals of chaotic and periodic motion. The chaotic trajectories in the phase space appear to lie on fractal attractors. 相似文献
20.
The threshold behaviour of pion production presented in our earlier work is successfully compared with the new SPEAR data. By using duality and sum rules we derive FT(π+)(x) ≈ FL(π+)(x) ≈ FT(π0)(x) ? FL(π0)(x) for x near 1. An accompanying results is for large s. 相似文献