首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A rotational analysis of the satellite bands of the β system of ZrO gives the splittings in the triplet states. For the lowest triplet state X3Δ, these splittings are:
δF1,2 = 287.9 ± 0.1 cm?1,
δF2,3 = 337.6 ± 0.4 cm?1.
  相似文献   

2.
Measurements have been made of the transit times of pulses of longitudinal and transverse ultrasonic waves propagating in single crystal LaB6 at room temperature. A unique set of values for the three independent elastic constants has been calculated from the resultant velocities and is; C11 = (45.33 ± 0.11) × 1011dynecm-2, C12 = (1.82 ± 0.17) × 1011dynecm2 and C44 = (9.01 ± 0.05) × 1011dyne/cm2. The Debye temperature of LaB6 from these measurements is 773 K, which agrees relatively well with the X-ray Debye temperature, however, differs much from the calorimetric and electrical resistance Debye temperatures.  相似文献   

3.
We study in detail the Lie-algebraical properties of the quantization condition for spinor fields
[a+i,a?j],a±i = ±2δija±j
.It turns out that the parafermi statistics is one particular solution of this relation: it is the minimal rank simple Lie algebra generated by the operators a±i entering into the above relation. We point out some other solutions.  相似文献   

4.
The Brillouin scattering techniques have been used to measure the velocity dispersion of hypersonic acoustic waves in the “high temperature” disordered cubic phase of adamantane. Shear waves, characteristic of the C44 elastic constant, show no significant dispersion. Longitudinal waves propagating in the (001) plane show strong velocity dispersion. The measures have been performed at the same temperature T = 295.7 K. Using a classical single relaxation time model for the dispersion as a function of frequency at temperature T, the L-mode data have been correctly fitted.The importance of the dispersion (C ? Co)C0 for the elastic constants is 20% for C11, 51% for C12 #1% for C44 and ?2.8% for (C11 ? C12)2. The fitted relaxation time is τ ? 9 × 10?11 sec.  相似文献   

5.
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   

6.
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   

7.
The third order elastic constants of RbCl, determined by measurements of the static stress dependence of ultrasonic waves, are found to be (in units of 1012dynescm2)
C111 = ?6.71 ± 0.1 C123 = 0.05 ± 0.07
C112 =?0.18 ± 0.04 C144 = 0.11 ± 0.02
C166 =?0.17 ± 0.01 C456 = 0.4 ± 0.01
. The calculation of third order constants using a rigid ion Born model is briefly discussed, and results are compared to the measurements. The comparison qualitatively supports the model, but no quantitative evaluation of the repulsive interaction is possible.  相似文献   

8.
The temperature dependence of the field emission flicker noise spectral density functions has been investigated for potassium adsorbed on tungsten (112) planes by a probe hole technique. By integration of the spectral density functions W(?) = Bi??gei the noise power (δn2Δ? for different frequency intervals Δ? is obtained. From the exponential temperature dependence of (δn2Δ? noise power “activation energies” qΔ? are determined. Plots of these energies versus coverage show a similar “oscillating” behaviour as recently found for W(?j) or (δn2Δ?j which indicates phase transitions of the adsorbed potassium submonolayers. The noise activation energies are discussed in terms of existing models and a comparison is made between the experimental q values and surface diffusion energies Ed as determined by conventional methods.  相似文献   

9.
The branching ratios are calculated for 11ΛB decay to the 11C ground and excited states below 8 MeV for two possible spin values of 11ΛB. It is found that the decay rate to the 11C state at E = 6.48 MeV is comparable in magnitude to that leading to the 11C ground state if J(11ΛB) = 52 is assumed. This result, unlike the branching ratios calculated for the J(11ΛB) = 72 case, is in accord with experiment and lends support to the assumption that J = 52 holds for 11ΛB. The necessity of the reinterpretation of some of the so-called 13ΛC events in terms of 11ΛB → π? + 11C1 is indicated.  相似文献   

10.
It is shown that for spinorial charges Q(L))α (α = 1, 2, L = 1, …, S) satisfying the commutation relations
{Q(L)α, Q(M)β} = εαβaLMQ,
{Q(L)α, Q(M)+β} = cσμαβPμδLM,
[Q(L))α, Pμ] = 0,
where Q is a scalar charge commuting with the spinor charges as well aswith the energy- momentum vector Pμ, there can exist several different multiplets for free massive scalar and spinor fields.  相似文献   

11.
The gradient-elastic tensor relating the electric field gradient tensor at the given nucleus to the elastic stress tensor was determined for aluminium to
C11 = 4·103dyn?12and C44 = ?6.7·103dyn?12
The comparison of the measured values with the point charge approximation indicates a dominant effect of the conduction electrons on the electric field gradient.  相似文献   

12.
The Mandel'shtam-Brillouin and Gross scattering was measured for a series of purified KBr crystals. The ratio IG2IMB, which for a pure, perfect crystal would be the Landau-Placzek ratio, was found to vary with the type of reactive gas treatment used in the final purification. With these crystals both the longitudinal and mixed mode bands were observed with θ and φ equal to 90°. The ratio ILIM was in agreement with calculated intensity ratios and the Δμ for these bands gave C11 + C12 = 41.6 GPa and C44 = 5.18 GPa.  相似文献   

13.
A millimeter-wave spectrometer having a sensitivity of 4 × 10?10 cm?1 in the 2-mm region has been constructed for observation of extremely weak millimeter-wave spectra of gases. It has been used to measure JJ, K = 0 ← 3 transitions in PH3 and JJ, K = 0 ← 3 as well as K = ±1 ← ±4 transitions in PD3. The B0 and C0 spectral constants (in MHz) are: for PH3, B0 = 133 480.15 ± 0.12 and C0 = 117 488.85 ± 0.16; for PD3, B0 = 69 471.10 ± 0.03 and C0 = 58 974.37 ± 0.05. The effective ground-state values obtained for the bond angle and bond length are: for PH3, r0 (A?) = 1.4200 and α0(o) = 93.345; for PD3, r0 (A?) = 1.4176 and α0(o) = 93.359. The corresponding zero-point-average values were calculated to be: for PH3, rz (A?) = 1.42699 ± 0.0002 and αz(o) = 93.2287; for PD3, rz (A?) = 1.42265 ± 0.0001 and αz(o) = 93.2567 ± 0.004. For both species, the equilibrium values are re (A?) = 1.41159 ± 0.0006 and αe(o) = 93.328 ± 0.02.  相似文献   

14.
The R band (26.5–40 GHz) microwave spectrum of 2,4-dioxabicyclo[3.1.0]hexan-3-one is reported. Rotational constants for the ground vibrational state of the common 12C41H416O3 and 13C1, 13C6 isotopically substituted species (the latter observed in natural abundance) have been evaluated. In addition rotational constants of the VB = 1 to VB = 5 quanta associated with the bending vibration of the five membered ring have been determined. A partial rs structure has been calculated:
r(C1?C5) = 1.497± 0.016 A?, r(C1?C6) = r(C6?C5) = 1.522 ± 0.015 A?
,
C6C1C5 = ∠C1C5C6 = 60°32′ ± 1°36′, ∠C1C6C5 = 58°′ ± 1°47′
. With certain assumed molecular information a least squares fit yields the following parameters:
β = 68.5 ± 0.02°, r(C1O2 = 1.408 ± 0.004 A?
,
C5C1O2 = 105.8 ± 0.02°, ∠C1O2C3 = 108.10 ± 0.03°
,
O2C3O4 = 112.8 ± 0.02°
.  相似文献   

15.
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   

16.
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   

17.
From the angular distributions of γ-rays emitted by oriented 129gTe and 129mTe nuclei implanted in iron by isotope separator, unique spin assignments could be made for the excited states of 129I at 487.4 keV (52+), 696.0 keV (112+), 729.6 keV (92+), 768.9 keV (72+), 1050.4 keV (72+) and 1111.8 keV (52+). In addition, E2/M1 amplitude ratios for the following 129I γ-rays (energies are in keV) are derived: δ(459.6) = ?(0.076+0.037?0.148); δ(487.4) = 0.50+0.17?0.10 or δ? = 0.35+0.15?0.09; δ(556.7) = 0.06±0.02 or δ? = ?(0.10±0.02); δ(624.4) = 0.10±0.26 or δ? > 0.4; the 696.0 keV γ-ray is pure E2; δ(729.6) = ?(0.34±0.06) or δ?1 = 0.55±0.05; δ(741.1) = ?(0.27±0.10) or δ?1 = ?(0.43±0.12); δ(817.2) = 0.46±0.04 or δ?1 =0.20±0.03 if Iπ (845 keV) = 72+; δ(1022.6) = ?(0.02 ±0.02) or δ?1 = ?(0.23±0.02); δ(1084) = 0.56 +0.04?0.14; δ(1111.8) = 0.06±0.05 or δ?1 = ?(0.08±0.05). The anisotropy of the 531.8 keV γ-ray excludes 12+ as a possible spin assignment for the 559.6 keV level, so that no 12+ level is fed in the decay from 129Te. Anisotropies for the 209, 250.7, 278.4 and 281.1 keV γ-rays are also measured. Comparison of the level scheme is made with theoretical predictions from both the pairing-plus-quadrupole model and the intermediate coupling unified model.  相似文献   

18.
Elastoresistances of TCNQ high conducting salts have been measured at room temperature by an original strain gauge technique. The effects, on the longitudinal and transverse resistivities ?, of an elementary uniaxial strain ? applied along one of the three axes, a, b or c1 respectively, have been estimated.For TTF-TCNQ, they are:
Kba =? ln ?b/??a = 16±3
;
Kbb = ? ln αb/??b = 34±4
;
Kbc1 =? ln ?/??c1= 24±8
(5% risk).So, in an hydrostatic pressure experiment, the fraction of piezoresistivity attributable to transverse effects is 43± 10% of the total value χb (Kba and Kbc effects accumulated).Low values have been found for the anisotropy (?a/?b) variations due to strains. So one may write:
Kaa = ? ln ?a/??a≌Kab
;
Kab = ? ln ?a/??b≌ Kbb
;
Kac1 = ? ln ?a/??c1 ≌Kbc1
.The TTF-, HMTTF-, TSF-, HMTSF-TCNQ elastoresistance values are coherent with the previously measured hydrostatic pressure piezoresistivity values.All these experimental results are in good agreement with a model where the longitudinal but also the transverse elastoresistivities are essentially due to variations with strains of the longitudinal scattering time τν defined by σb = ne2τν/m1.  相似文献   

19.
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   

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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号