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1.
J = 1 ← 0 and J = 2 ← 1 transitions in 35ClCN and 37ClCN were measured using a C-band waveguide spectrometer and phase-locked sources. Parameters obtained from the data are: B(35ClCN) = 5 970.820 ± 0.010 MHz, B(37ClCN) = 5 847.246 ± 0.008 MHz, eqQ(35Cl) = ?83.26 ± 0.04 MHz, eqQ(37Cl) = ?65.61 ± 0.04 MHz and eqQ(14N) = ?3.60 ± 0.08 MHz.  相似文献   

2.
Relative oscillator strengths in the Cameron system of CO(a3Π ← X1Σ) have been observed in absorption for six bands (υ′ = 0–5, υ″ = 0) with the result, normalized to the absolute (0, 0) band measurement of Hasson and Nicholls, ?00 = (1.62±0.07) × 10?7, ?10 = (1.96±0.09) × 10?7, ?20 = (1.41±0.04) × 10?7, ?3 0 = (0.72±0.03) × 10?7, ?40 = (0.31±0.02) × 10?7, ?50 = (0.14±0.01) × 10?7. The density of CO was modulated with a motor-driven vacuum valve and synchronous fluctuations (?1 per cent) in the transmitted intensity detected with a lock-in amplifier. Peak pressure in the 21 cm absorption cell was approximately 10 torr. A curve of growth analysis was used to correct saturation effects by less than 3 per cent.  相似文献   

3.
The g-factor and mean life of the 52+1 state at 3.85 MeV in 13C have been determined by a recoil-into-vacuum plunger measurement. The state was populated by the 2H(12C, p) reaction at E = 15.0 MeV. The analysis of the time-differential deorientation effect on the p-γ angular correlation leads to a g-factor of ¦g¦ = 0.558 ± 0.015. For the mean lifetime a value of τ = 12.2 ± 0.4ps is obtained.  相似文献   

4.
The results of integral precession measurements are reported for 32+ and 52+ excited states in 123,125Te. The measurements were made using the ion implantation perturbed angular correlation technique by recoiling the excited nuclei into polarized iron. The measured mean lifetimes and g-factors are: 123Te (440 keV, 32+) τ = 39±4 ps, g = 0.34 ± 0.06; (505 keV, 52+) τ = 26±3 ps, g = 0.04±0.025; and 125Te(443 keV, 32+) ρ = 27±3.3 ps, g = 0.39±0.06; (464 keV, 52+) g = 0.12±0.04. The results are compared with theoretical predictions.  相似文献   

5.
Lifetimes of low-lying states in 19F were measured using the Doppler-shift attenuation method through the 15N(α, γ)19F reaction. Values of τm = 3700 ± 700 fs (1.35 MeV), 140 ± 15 (1.46), 19 ± 7 (4.00) and 63 ± 19 (4.03) were obtained for the lowest 52?, 32?, 72? and 92? members, respectively, of the Kπ = 12? rotational band and 5 ± 3 fs (1.55 MeV) and 370 ± 25 (2.78) for the 32+ and 92+ members of the Kπ = 12+ ground-state band. For the Doppler-shift attenuation analysis correction factors of the nuclear and electronic stopping powers were determined by measuring the Doppler-shift attenuation and γ-ray line shape of the 2.78 → 0.20 MeV transition and range values of 100, 200. 300 and 370 keV 19F nuclei in tantalum. All calculations were done with Monte Carlo methods. The transition strengths are discussed in terms of different theoretical predictions.  相似文献   

6.
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   

7.
We report a measurement of the forward-backward asymmetry in the radiative capture of polarized cold neutrons in the reaction 35Cl(n, γ)36Cl where 36Cl is in the ground state. The measured value of the asymmetry is a = (1.57 ± 0.531) × 10?4. We deduce the mixing between the 2+ capture level and the neighboring 2? levelto be 〈2?¦Hp.v.¦2+〉 = ?0.25 ± 0.08 eV before corrections. A measurement of the integral asymmetry of all γ-rays in the neutron capture by 35Cl leads to agreement with measurements at Leningrad.  相似文献   

8.
Cyclotron resonance of electron and holes have been optically detected at 70 GHz and at 1.8 K in n-type CdTe. The bare effective masses, in unit of the free electron mass, are found to be: m1 = 0.088 ± 0.004, m1lh = 0.12 ± 0.01, m1 = 0.60 ± for H // <100>, and m1e = 0.089 0.004, m1lh = 0.11 ± 0.01, m1hh = 0.69 ± 0.02 for H // <111>. The Luttinger valence band parameters deduced from these measurements are: γ1 = 5.3 ± 0.5, γ2 = 1.7 ± 0.3 and γ3 = 2.0 ± 0.3, in fair agreement with the calculations of Lawaetz.  相似文献   

9.
Primary capture γ-rays have been studied for 38 177Hf neutron resonances with energies in the range 1–165 eV. Intensities were measured for 29 transitions ending at states with an excitation energy in 178Hf up to 2050 keV. The analysis was facilitated by the previous knowledge of the spin and parity of all neutron resonances and of most low-lying states. For nine final levels, which had not previously been seen, information on J and π was deduced from the corresponding average intensities. The distribution of partial widths was fitted with a χ2 function with ν = 1.38?0.13+0.18 degrees of freedom for E1 radiation and ν = 1.5?0.40+0.60 for M1 radiation. The average El reduced photon strength was found to be SEl = 〈Γγitij/DEγ5〉A?83 = (4.8 ± 1.0) × 10 ?15MeV?5 and the ratio between El and Ml intensities equal to 5.5 ± 1.4. A comparison of this value for the El strength with those reported for other nuclei with A$?= 100 showed that the intensities follow the A-dependence predicted by the Brink-Axel model. A non-statistical effect was observed, consisting of an enhancement of El transition probalilities to K = 2, 3 final states as compared to K = 0, 4 states.  相似文献   

10.
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   

11.
Mössbauer-effect studies yield the following nuclear parameters: In 155Gd, Q(86)/Q(0) = 0.087 ± 0.006, Q(105)/Q(0) = 1.00 ± 0.03. In 156Gd, g(89) = 0.386 ± 0.004, 156Q(89)/155Q(0) = ?1.51 ± 0.02. In157Gd, Q(64)/Q(0) = 1.80 ± 0.03 and g(64) = ?0.185 ± 0.005. The value of g(89) is in very good agreement with the theoretical value.  相似文献   

12.
Experiments on (ft)+/(ft)? for mirror Gamow-Teller β-decay are reanalyzed in the light of recent work and new values for the Kubodera, Delorme and Rho second class parameters are deduced: ξ = ? (0.8 ± 2.0) × 10?3MeV?1; λ = (3.4 ± 3.9) × 10?3. These values are compared with recent correlation experiments.  相似文献   

13.
The reorientation effect in Coulomb excitation has been used to measure the following static quadrupole moments: Q2 + (32S) = ?0.066 ± 0.017 b, Q2 + (34S) = 0.026 ± 0.023 b, Q2 + (204Pb) = 0.19 ± 0.14 b. Interference effects from higher excited states have been included in the analysis, with the signs of the E2 matrix elements taken from an anharmonic model. The value obtained for Q2 + (32S) is in disagreement with two previous measurements. We attribute the discrepancy to the smaller internucleon separation distances involved in the previous experiments, which can cause deviations from Coulomb excitation cross sections. The other quadrupole moments have not been measured previously. The B (E2: 0+ → 2+) measured were: 0.0305 ± 0.0016 e2 · b2(32S), 0.025 ± 0.004 e2 · b2(34S), and 0.166 ± 0.009 e2 · b2(204Pb). From the angular distribution of the de-excitation γ-rays of the Pb nuclei following recoil into vacuum, we have determined the following g-factors: ¦g2 + (204Pb)¦ < 0.08 (two standard deviations), ¦g2 + (206Pb)¦ = 0.07+ 0.07? 0.03. Our value of g2 + (206Pb) is in agreement with a previous measurement.  相似文献   

14.
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   

15.
High resolution spectra of the ν3 band of methane, 12CH4, were recorded by using a “third generation vacuum Fourier interferometer”; a large pressure range (from 0.009 to 10 Torr) with a sample path fixed at eight meters was used, enabling observation of transitions with intensity ratios as low as 110 000. More than 350 forbidden transitions of the ν3 band, including about 125 transitions of the Q+ branch, were unambiguously identified. Of the 277 transitions retained for computations, one-hundred have 11 ≤ J ≤ 16. From combination difference relations using pairs of transitions having the same upper state energy level (forbidden-allowed and forbidden-forbidden pairs were used), 276 independent differences between ground state energy levels could be determined with uncertainties of about 0.001 cm?1.These data yielded the following values for the ground state structure constants of 12CH4 along with their standard deviations (in cm?1): βohc=5.2410356±0.0000096, γohc=(?1±0.00074) 10?4, πohc=(5.78±0.18) 10?9, ?ohc=(?1.4485±0.0023) 10?6, ?ohc=(1.768±0.126) 10?10, ξohc=(?1.602±0.067) 10?11, Thus, for the first time, the scalar constant π0 has been evaluated and ir values have been obtained for the two tetrahedral constants ?0 and ξ0; furthermore, these values are in very good agreement with the ones recently determined from radiofrequency data, i.e., in cm?1: ?ohc=(?1.45061±0.00014) 10?6, ?ohc=(1.7634±0.0068) 10?10, ξohc=(?1.5432±0.0040) 10?11 From these values, the 276 differences can be reproduced with an overall rms deviation equal to 0.0009 cm?1.Finally, the ground state energies of 12CH4 have been calculated for J ≤ 16.  相似文献   

16.
Using a recent theoretical method, the ratio of nuclear matrix elements R = (vF0220?√32AF0221/vF0211) 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 (L1 + L2)K = 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   

17.
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   

18.
The first results are reported on the Pn values obtained with the recoil focussing parabolatype mass separator for unslowed fission products Lohengrin installed at the Grenoble high flux reactor. The mass chains studied were 90, 91, 93, 94, 95, 99, 134, 137, 138 and 139. Both the neutron and the β activities were measured simultaneously. The technique used to measure the neutron and the β activities and the method of analyzing the experimental data are discussed in detail. The present work led to: (i) three new periods corresponding to the new isotopes of selenium (91Se, T12 = 0.27±0.05 sec), strontium (99Sr, 0.6±0.2 sec) and telurium (138Te, 1.3±0.3 sec); (ii) accurate periods of 99Y(T12 = 1.45±0.22 sec) and134Sn (0.7±0.2 sec); (iii) four new delayed neutron precursors consisting of 91Se, 94Kr, 99Sr and 138Te; (iv) six new Pn values corresponding to the precursors 91Se (Pn = (21±10)%), 94Kr ((5.7±2.2)%), 99Sr ((3.4±2.4)%), 99Y ((1.2±0.8)%), 134Sn ((17±13)%) and138Te ((6.3±2.1)%); (v) a precise Pn value of the precursor 137Te ((2.5±0.5)%); (vi) a redetermination of the Pn values of the precursors 90, 91Br, 93Kr, 93, 94, 95Rb and 137, 138, 139I. The results of this work are discussed and compared with the existing data. The low level sensitivity of the present detection system is determined to be Pn(m)Yq(m) ? 0.4 × 10?6n/f (where Yq(m) is the cumulative yield for the mass m and the ionic charge q).  相似文献   

19.
The intrinsic structure of 168Tm has been studied using the (3He, d) and (α, t) proton stripping reactions as well as the (d, t) and (3He, α) neutron pick-up reactions. The beams of 24 MeV 3He particles, 25 MeV α-particles and 12 MeV deuterons were obtained from the McMaster tandem Van de Graaff accelerator. The reaction products were analyzed with an Enge-type magnetic spectrograph and detected with photographic emulsions. The spectra have been interpreted in terms of the coupling of an odd proton and an odd neutron, each moving independently in a spheroidal potential, which gives rise to intrinsic two-quasiparticle states with K = ¦Ω1±Ω2¦. The identification of the intrinsic states was made by comparing the experimental cross-section patterns with those predicted with the aid of Coriolis coupling and distorted-wave Born approximation (DWBA) calculations. Rotational bands superimposed on the Kπ = 3+ and Kπ = 4+, {72+ [633]n±12+ [411]p} configurations, the first of which is the ground state, ha been observed in the spectra of all four reactions. New assignments have been made for configurations resulting from coupling the 12? [541], 72+ [404], 54+ [402] and 12? [530] p to the 72+ [633] neutron state. The neutron pick-up measurements confirmed the earlier assignments based on (d, t) reaction studies and suggested tentative assignments for the {12+ [400]n±12+ [411]p} and {32+ [402]n±12+ [411]p}  相似文献   

20.
The first observation of cyclotron resonance in p-type InP is reported. The holes were thermally excited at 110 K and the resonance was observed at 337μm wavelength (HCN laser) using a pulsed magnetic field of 0–350 kG. The effective masses of the light and heavy holes in the 〈111〉 direction were found to be m1L = 0.12 ± 0.01 m0, m1H = 0.60 ± 0.02 m0 and in the 〈100〉 direction m1L = 0.12 ± 0.01 m0, m1H = 0.56 ± 0.02 m0. We obtain an estimate of the Dresselhaus parameters A = ?5.04, |B| = 3.12, C2 = 6.57. We also report the effective masses for p-type GaP in the 〈111〉 direction as m1L = 0.18 ± 0.02 m0, m1H = 0.56 ± 0.04 m0.  相似文献   

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