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.
The rs structure of thioformamide has been determined from the microwave spectra of the normal as well as isotopic species of the molecule. The structural parameters obtained assuming the planarity of the molecule are NHc = 1.0018 ± 0.006 A?, NHt = 1.0065 ± 0.003 A?, CN = 1.3582 ± 0.003 A?, CS = 1.6262 ± 0.002 A?, CHa = 1.096 ± 0.08 A?, ?HcNHt, = 121°42′ ± 40′, ?HcNC = 117°55′ ± 40′, ?HtNC = 120°22′ ± 30′, ?NCS = 125°16′ ± 15′ ?NCHa = 108°5′ ± 5°, and ?SCHa = 126°39′ ± 5°.The dipole moment is calculated from the Stark effects of the three transitions to be μa = 3.99 ± 0.02 D, μb = 0.13 ± 0.25 D, and μtotal = 4.01 ± 0.03 D, where the c component is assumed to be zero.The quadrupole coupling constant of the 14N nucleus is estimated using the doublet splittings observed for six Q-branch transitions; χcc - χbb = ?5.39 ± 0.15 MHz and χaa = 2.9 ± 1.2 MHz.Two sets of vibrational satellites are observed and assigned to the first excited state of the amino wagging and the NCS bending vibrations, respectively. The relative intensity measurement gives the vibrational energies of 393±40 cm?1 and 457 ± 50 cm?1 for NH2CHS and 293 ± 30 cm?1 and 393 ± 40 cm?1 for ND2CHS. The amino wagging inversion vibration in the molecule is discussed in comparison with that in formamide. It is most probable that the thioformamide molecule is also planar without any potential hump to the amino inversion at the planar configuration.  相似文献   

2.
We measured the differential cross section for p?p and pp elastic scattering in the momentum-transfer range 0.01 <|t| < 1.0 GeV2 at the CERN Intersecting Storage Rings with center-of-mass energy s = 52.8 GeV. Fitting the differential cross section with an exponential [Aexp (bt)], we found bpp = 13.92 ± 0.59 GeV?2 for |t| < 0.05 GeV2, whilst for |t| > 0.09 GeV2, bpp = 10.68 ± 0.26 GeV?2. Using the optical theorem, we obtained for the total cross section σtot(pp)= 44.86 ± 0.78 mb and, by integrating the differential cross section, we obtained for the total elastic cross section σel(pp) = 7.89 ± 0.28 mb. Calculations of σtot combining elastic-rate and total-rate measurements are also given. All of these measurements were also performed for pp scattering at the same energy, and the results for both reactions are compared.  相似文献   

3.
The parity violating E1-amplitude for the 6S–7S transition in cesium has been calculated from first principles: 〈7S|Dz|6S〉 = (0.88 ± 0.03) × 10?11 (?QWN)(?ieaB), where QW is the weak nuclear charge, N is the number of neutrons, and aB is The Bohr radius. The experimental data from Bouchiat et al. make it possible to find QW = ?73.4 ± 8.1 ± 6 and the Weinberg angle sin2θW = 0.237 ± 0.036 ± 0.03. To control the accuracy, the energy levels, the fine and hyperfine structure intervals and the oscillator strenghts in the S-P transitions in Cs have been calculated.  相似文献   

4.
For the S = 12 XY model at T = 0 four susceptibilities have been calculated exactly on a sequence of finite square lattices and extrapolated to the infinite square lattice. For the ferromagnet χzz = 0 while χxxN2.9; for the antiferromagnet JχxxN(gμB)2 = 0.025 ± 0.002 and JχxxN(gμB)2 = 0.13 ± 0.03.  相似文献   

5.
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   

6.
An extensive study of the microwave spectrum of cyanamide has been undertaken, the analysis being based in part on semirigidbender calculations by the methods of Bunker and Szalay. Inversion lines of NH2CN, K?1 = 2 aQ branches and a number of vibrational satellites of the J = 2?1 transition were observed. A two-vibrational-state Hamiltonian was used to fit simultaneously the 0+ and 0? microwave data and yielded rotational constants X, Y, Z, DJ, DJK, d1, HJK as well as the inversion splitting and the μyz-connecting matrix element. Vibrational satellite data of seven isotopic species and infrared frequencies of NH2CN were included in the semirigid bender calculations: The NCN spine is nonlinear by ca. 5° in the equilibrium structure of the molecule. Also, rNHA? = 0.9994 + 0.0144?2; <HNH/2 = 60.39° ? 0.1134?2; rNCA? = 1.3301 + 0.0327?2 (? is the inversion angle in rad); rCN = 1.1645 A? fixed. The inclusion of the NC bond flexing was necessary in order to reproduce the observed vibrational satellite patterns of NH2CN, NHDCN, and ND2CN. The barrier to inversion of the amino group is 510 ± 6 cm?1 with minima at ±45.0 ±0.2°. The inversion dipole moment is 0.91 ± 0.02 Debye.  相似文献   

7.
The phase φ+? is evaluated on the basis of measurements of the KS-KL interference in the π+π? decay mode and the mass difference Δm, both reported previously by this group. The result is: φ+? = 45.9° ± 1.6°. This, together with previous results on +?|, |η00η+?| and the charge asymmetry δ in leptonic decay, is compared with the prediction of the superweak model, with good agreement.Finally the result is used to find, on the basis of unitarity, a new upper limit on CP violation in the decay K0 → 3π0. This limit is |η000|2? 0.21.  相似文献   

8.
E. Hagn  E. Zech 《Nuclear Physics A》1982,373(2):256-266
The magnetic hyperfine splitting vM=|gμNBHF/h| of 196mAu (jπ=12?; configuration ¦(π112(v132+)〉12?; T12 = 9.7 h) 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 π12? and v132+ isomeric states in the neighbouring odd Pt, Au and Hg nuclei the structure of the 12? state is discussed.  相似文献   

9.
The magnetic hyperfine splitting νM = |NBHF/h| of 193mAu (jπ = 112?, E = 290 keV; T12 = 3.9 s) as a dilute impurity in Ni has been measured with nuclear magnetic resonance on oriented nuclei as 226.4(2) MHz. With the known hyperfine field BHF = ?264.4(3.9) kG corrected for hyperfine anomalies the g-factor and magnetic moment of 193mAu are deduced to be |g| = 1.123(17) and |μ| = 6.18(9) μN.  相似文献   

10.
Two-magnon Raman scattering in the planar quadratic antiferromagnet K2FeF4 is investigated. The temperature dependence of the energy shift is in good agreement with second-order Green-function theory, as is the linewidth at low temperature. Numerical results, including renormalization, are the Heisenberg exchange JkB = ?14.5 ± 0.7 K and the anisotropy Δ(T = 0) = gμBHA4|J|S = 0.18 ± 0.05, but with J[1 + Δ(T = 0)]kB = ?17.06 ± 0.10 K.  相似文献   

11.
Gauge theories of weak and electromagnetic interactions involving Han-Nambu quarks are constructed with the following features: small KL → μμ amplitude and KL - KS mass-splitting; a non-leptonic effective Lagrangian ΔY = ± 1 leading to the usual soft-pion theorems and obeying a fundamental |ΔI| = 12 rule, with corrections of order θ2Cabibbo.  相似文献   

12.
Internal rotation A-E splittings have been observed in the ground state for both 35Cl and 37Cl isotopic species of S-methylchlorothioformate. The values V3 (35Cl) = 893 ± 20 and V3(37Cl) = 890 ± 20 cal/mole have been obtained. The anaalysis of the hyperfine structure gave χaa(35Cl) = ?49.2, χbb(35Cl) = 22.4 and χaa(37Cl) = ?39.0, χbb(37Cl) = 18.3 MHz. Only the syn-conformation of the methyl group with respect to the carbonyl group has been observed. A partial r0 structure is given.  相似文献   

13.
We investigate the properties of a quasi-unidimensional system which exhibits Peierls instability at Tc(μ), where μ is the Fermi energy as measured from the middle of the conduction band. Tc(μ) decreases as 6μ6 increases. The phonon-drag diagrams contribute to fluctuation conductivity, which is proportional to (T ? Tc)?12, if |μ| > 1.056 Tc(0). The Kohn Anomalies do not occur at 2kF unless μ = 0 or |μ| ? T.  相似文献   

14.
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   

15.
Exact inverse solutions to the integral equation φ(rs|r0, k) = ?D3f (r, ω)g(r|r0, k)g(r|r, k)d3r, where g(r|rj, k); j = 0 or s is the free space Green function, are derived in plane and cylindrical coordinates for fixed ω. These solutions allow an inelastic scattering potential f(r, ω) which is of compact support r ? D3 to be recovered from scattering data collected over the surfaces of a plane and cylinder respectively.  相似文献   

16.
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   

17.
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   

18.
The ratio between the cross sections for the reactions π? p→ χ?0n and π?pη→2γ n has been measured to be (2.4 ± 0.9) × 10?2, (2.1 ± 0.6) × 10?2 and (2.8 ± 1.3) × 10?2 at 3.8,6,8 and 12 GeV/c incident momentum respectively.At the same momenta the cross section for πt- p → neutrals is (1.48 ± 0.09) mb, (0.86 ± 0.05) mb, (0.64 ± 0.04) mb and (0.42±0.03) mb.  相似文献   

19.
AC susceptibility, magnetization and electrical resistivity around the Curie temperature (Tc) were measured for Fe15Ni65B18Si2 glass. The results yield Tc = (307.6±0.1) K and the following critical exponents γ = 1.50±0.03, β = 0.375±0.01, δ = 5.1±0.1 andα = -0.29±0.05. These values were obtained in the reduced temperature interval 1×10-3 ?|T?Tc|Tc?5 ×10-2. In spite of the fact that these values for the critical exponents were obtained from different measurements they obey the equality relations γ = β(δ?1) and γ+2β+α = 2. Reduced magnetisation and field follow a magnetic equation of state derived for a second-order phase transition over a wide temperature range. This set of critical exponents is compared with those derived from the Heisenberg model as well as with the usual ones for a pure crystalline ferromagnets. The comparison shows that the values of |α| and γ, for our alloy, are considerably larger than those from the model and the usual crystalline ones. A similar difference is also observed in some other amorphous and dilute crystalline ferromagnets and is probably due to magnetic inhomogeneities.  相似文献   

20.
The Stark and Zeeman effects in methyl silane in the ground vibronic state have been studied in detail using the molecular-beam electric-resonance method. For a symmetric rotor without internal rotation, the rotational dependence of the effective dipole moment for matrix elements diagonal in J has been shown by Watson, Takami, and Oka to have the form μQ = μ0 + μJJ(J + 1) + μKK2. It is shown here that, to this order, a complete characterization of the Stark effect requires only one more parameter, namely, the effective anisotropy (α| - α)eff in the polarizability. From Stark measurements alone, the true anisotropy cannot be separated from the additional dipole distortion constant shown by Aliev and Mikhaylov to enter dipole matrix elements off-diagonal in J. By studying nine different transitions (J, K, mJ) → (J, K, mJ ± 1) in CH328SiH3, values were obtained for the four Stark parameters: μ0 = 0.7345600(33) D, μJ = 8.83(35) μD, μK = ?32.82(37) μD, and (α| - α)eff = 1.99(16) × 10?24 cm3. These errors reflect only the internal consistency in the data; the absolute error in μ0 is 32 μD. The modification of the Stark effect by internal rotation is discussed; it is shown that the only significant effect here is to modify the interpretation of μ0. The change in μ0 upon isotopic substitution of 30Si for 28Si was determined: μ0(30Si) - μ0(28Si) = 67.0(2.0) μD. A study of molecular magnetic effects in CH328SiH3 has yielded the two molecular g factors, g = ?0.036391(21) nm and g| = ?0.10667(13) nm, as well as the anisotropy in the susceptibility | - χ) = ?44.9(2.3) × 10?30JT2. The molecular quadrupole moment has been calculated.  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