A weak coupling calculation for the A = 14 nuclei

A calculation of the A = 14 levels is performed by using the weak coupling approach. Very good agreement with experiment is obtained as all known levels below 13 MeV in ¹⁴N are satisfactorily explained. A few additional states are predicted to be found. The electromagnetic transition strengths are calculated and reproduce the experimental values in almost all cases. In particular, a simple calculation of the isospin mixture of the negative-parity states provides an explanation of the known T-forbidden E1 transitions. Also the reduced proton widths are considered and are found to be consistent with (p, p) scattering experiments on ¹³C.     

Critical behavior of the E.S.R. line widths in a quasi two-dimensional antiferromagnet MnTiO3

The critical behavior of the electron paramagnetic resonance line widths have been studied in the quasi two-dimensional antiferromagnet MnTiO₃. Line widths diverge like ΔH∝(T?T_N)^?0.49, which is in good agreement with the theoretical value predicted by Kawasaki.     

Strengths and air-broadened widths of H2O lines in the 2950–3400 cm-1 region

Measurements of the strengths and air-broadened widths of 223 lines of water vapor have been made with high resolution in the region 2950–3400 cm^-1. The strength data of the lines in the 2ν₂ and ν₁ bands are analyzed to determine the band strengths and the coefficients of the F factors. The band strengths of the 2ν₂ and ν₁ bands were found to be 1.75±0.08 and 10.3±1.1 cm^-2 atm^-1 at 296 K, respectively. The selection rules of the lines observed in the ν₃ band are forbidden in the symmetric-rotor limit. The majority of the measured strengths of these lines differ from the calculated values because of different asymmetries in the upper and lower vibrational states. Also, Coriolis perturbations in several lines of the ν₁ and ν₃ bands were observed in the strength measurements. The direct method was applied to determine the air-broadened line widths. The results are compared to the computed values of Benedict and Kaplan. There is good agreement between this work and the computed results for line width values greater than 0.05 cm^-1 atm^-1. However, for line widths less than 0.05 cm^-1 atm^-1, the measured values are smaller than the computed widths. A value of 0.018 cm^-1 atm^-1 is given for the width of the line at 3378.071 cm^-1, whereas the calculated value is 0.032 cm^-1 atm.     

Self-broadened widths and absolute strengths of 12CH4 lines in the 1310–1370 cm-1 region

Self-broadened widths and absolute strengths of ¹²CH₄ lines in the 1310–1370 cm^-1 spectral region have been measured at room temperature (296 K) using Fourier transform absorption spectroscopy with a 0.003 cm^-1 resolution (FWHM unapodized). The line widths, which are the most comprehensive set of measurements on self-broadened lines in the ν₄ R-branch yet reported, show a tetrahedral-symmetry dependence, which is consistent with recently reported observations. Generally, the line strengths are approximately 5% higher than those tabulated on the AFGL line-parameter compilation.     

Collisional broadening and line intensities in the ν2 and ν4 bands of PH3

Using a tunable diode-laser spectrometer self-broadening coefficients and absolute intensities have been measured for 26 lines of PH₃ at 298 K in the QR branch of the ν₂ band and the PP and RP branches of the ν₄ band. The recorded lines with J values ranging from 2 to 14 and K from 0 to 11 are located in the spectral range 995-1093 cm⁻¹. Self-broadening coefficients have also been measured at 173.4 K for nine of these lines. The collisional widths and line strengths are obtained by fitting each spectral line with different theoretical profiles. The results obtained for the line intensities are in good agreement with recent measurements [J. Mol. Spectrosc. 215 (2002) 178]. The self-broadening coefficients are also calculated on the basis of a simple semiclassical model involving only the electrostatic interactions. A satisfactory agreement is obtained except for high J values or K values equal to J, for which the calculated results are notably underestimated. By comparing broadening coefficients at room and low temperatures, the temperature dependence of these broadenings has been determined both experimentally and theoretically.     

Long-range dependence in tree-ring width time series of Austrocedrus Chilensis revealed by means of the detrended fluctuation analysis

By using the detrended fluctuation analysis and detrended moving average method, 823 time series of tree-ring widths in Austrocedrus Chilensis in Patagonia were analyzed. The tree-ring widths of A. Chilensis have been widely used for climatological studies. The results point out to the presence of significant scaling in the temporal fluctuations of tree-ring, which is not due to singular probability density function of the widths but due to the presence of long-range correlations. Such results are in good agreement with those concerning the evidence of long-range dependencies in weather time series.     

Empirical formula for energy level shifts of pionic atoms

An empirical formula for energy level shifts of pionic atoms is proposed. Numerical results show remarkably good agreement with experimental data. We predict energy level shifts and widths for pionic deuterium, tritium and helium. With these values, scattering lengths of π-d, π-t and π-³He are also calculated. The results are (in fm) ?0.083 + 0.024 i, ?0.287 + 0.028 i and 0.067 + 0.035 i, respectively.     

Resonances of Dirac Particle in the Yukawa Potential

We applied the complex scaling method to study the resonances of a Dirac particle in the Yukawa potential, and obtained the corresponding energies and widths. In the non-relativistic limit, our results are in excellent agreement with those by non-relativistic calculations with J-matrix approach. Furthermore, we found that the energies and widths of spin doublets are approximately degenerate, and preserve a good spin symmetry. The quality of spin symmetry is correlated with the parameters of the Yukawa potential.     

Theory of cyclotron resonance width for electrons inelastically scattered by phonons

The cyclotron resonance width for a semiconductor under extreme high fields is calculated with the assumptions that electrons are scattered by acoustic phonons inelastically. The numerical results are in very good agreement with the recent experiments on Ge by Miura et al. (T ～ 300 K, B ～ 97 tesla). The energy-dependent widths arising from the relaxation processes with absorption and emission of a phonon show quite distinctive behaviors at low electron energies. At extreme low temperatures when few phonons are present, the width arising from the zero-point motion of the lattice is finite but very small. The charged-impurity scattering with the density as low as 10¹² cm^?3 numerically dominate the width due to the electron-phonon interaction below 10 K. The present theory supplements the previous work by Suzuki et al. where the elastic-scattering and high-temperature approximation were used.     

Soliton modulation-widths for Pb1−xSnxTe TO-ponons

Some new TO-phonon width data for Pb_1?xSn_xTe with strong temperature-dependence are explained in terms of a “modulation-effect” due to non-linear lattice modes. Reasonable values of the parameters provide very good agreement with the experimental widths.     

Stark broadening and shift of some isolated spectral lines of singly ionised earth alkaline metals

Using aZ pinch discharge as a plasma source the profiles and shifts of some prominent ion lines of earth alkaline metals were measured and compared with Stark broadening theories and other experimental results. An electron density of 3.1 to 10.3×10¹⁶ cm^?3 was determined by the laser interferometry, while the electron temperature in the range 25100 to 34800 °K were measured from relative intensities of spectral lines. Comparison of reported experimental shifts and widths with the theories both semi-classical and quantum mechanical shows good agreement. It was also found that Griem's semi-empirical formula is useful and accurate for line widths evaluation.     

Hidden-gauge model and radiative decays

We consider the radiative decay widths in a hidden-gauge model. For calculating the decay widths we use the anomalousVVP Lagrangian.g _VVP is a function off _P due to the symmetry breaking effects. It is shown thatf _P is consistent with that obtained by the one-loop calculation. A reasonable agreement with the experimental decay widths is achieved.     

Calculation of Xe II line strengths and radiative lifetimes in intermediate coupling

Line strengths for 5s ² 5p ⁴ 6s?5s ² 5p ⁴ 6p transition in xenon are calculated in intermediate coupling scheme. The parametric potential method is used in calculating the radial part of the wave functions while the method of least squares fit of energy levels is applied in obtaining the angular part of the wave functions. Lifetimes of the 6p states obtained using these methods show a good agreement with data from electron-impact experiments.     

Competition between fission and neutron emission by diffusion model

Magnitudes and relative signs of amplitudes for three inelastic proton channels have been determined for 42 3/2⁺ resonances in⁵⁷Co in the rangeE _p =3.1–4.0 MeV. Amplitude and width channel correlations have been obtained for each pair of channels. One of the amplitude correlations is large and highly significant. Comparisons between these data and statistical theories of nuclear levels are presented for both widths and products of amplitudes; in general, agreement is good. The widths for one channel and amplitude products for one pair of channels appear energy-dependent, with most of the strength concentrated in the lowest 200 keV.     

金等离子体中Au51+能级寿命的相对论多组态计算

根据扩展的相对论多组态 Dirac-Fock理论,采用"多功能相对论原子结构程序(Grasp2) ",选用二参数Fermi有限核模型计算类镍Au51+ 的能级寿命和能级宽度及光谱跃迁波长、跃迁几率和振子强度,计算所得波长值与实验值符合得很好,能级寿命与能级宽度的大小关系符合海森堡的能量与时间测不准原理.     

Open flavour charmed mesons in a quantum chromodynamics potential model

We modify the mesonic wave function by using a short distance scale r ₀ in analogy with hydrogen atom and estimate the values of masses and decay constants of the open flavour charm mesons D, D _s and B _c within the framework of a QCD potential model. We also calculate leptonic decay widths of these mesons to study branching ratios and lifetime. The results are in good agreement with experimental and other theoretical values.     

A pseudopotential calculation of the phonon spectrum of aluminium

The phonon dispersion curves for Al are calculated from a theory based on Coulomb interactions among the ions and a local pseudopotential interaction between ions and conduction electrons. Conduction electron correlations are taken into account according to a theory of Singwiet al. ^1,2. A dielectric constant is constructed which satisfies the compressibility sum rule. This is especially important for longitudinal phonons. The agreement of the computed frequencies with the experimental dispersion curves of Stedman and Nilsson³ is good. Sites, sizes and widths of Kohn anomalies in the dispersion curves are also calculated. As expected the theoretical curves show larger anomalies than the experimental data. Finally a comparison is made with the recent calculations of Wallace⁴.     

Unrestricted Hartree-Fock calculations for a cluster model of NiO

Self-consistent restricted and unrestricted Hartree-Fock calculations have been performed for a NiO₆^?10 cluster embedded in a point ion field. The unrestricted Hartree-Fock calculations give rise to p-like and d-like states whose energies overlap, but which are essentially non-interacting. The calculated widths of the p-like and d-like states are 4.5 and 2.2 eV respectively, in good agreement with experiment. Furthermore, d-orbital relaxation is found to be much more important for RHF calculation as opposed to UHF calculations.     

Theoretical calculation of electron impact widths and shifts of XeII lines

Summary The shifts and widths of prominent XeII transitions are calculated in the semi-empirical approach; a very good agreement with experimental values is obtained. The oscillator strengths were calculated using complete intermediate coefficients after energy matrix diagonalization. The author of this paper has agreed to not receive the proofs for correction.     

Single-Proton states of159Ho studied with the (p,α) reaction spectroscopic evidence for the unusual coriolis strengths in159, 161, 163Ho nuclei

The proton-hole character of states in¹⁵⁹Ho has been studied using the^{162, 164}Er(p, α)^{159, 161}Ho reactions with 17 MeV protons. The shapes of angular distributions measured for both nuclei were compared, with good agreement in most cases, to tritoncluster-transfer DWBA calculations. The deviations obtained and the experimental normalization factors deduced for the¹⁶⁴Er(p, α)¹⁶¹Ho reaction by comparisons to (t, α) cross sections indicate a need for a revised treatment of the mechanism of the (p, α) reaction on deformed nuclei. By comparisons to the well-known states in¹⁶¹Ho, nuclear structure factors were obtained for many levels in¹⁵⁹Ho. The Nilsson assignments for the 3/2⁺[411], 5/2^?[532] and 5/2⁺[413] bands were confirmed and the lowest rotational members of these bands were established. The anomalous strengths of the strongly mixed positive parity states in^{159, 161, 163}Ho are discussed in the frame-work of the Nilsson model with the pairing and effective Coriolis strengths included. The Coriolis strengths giving best fits to excitation energies also improve the agreement of theory with the experimental nuclear structure factors. Rotational spacings of the 5/2⁺[413] and especially those of the 5/2^?[532] bands in^{159, 161, 163}Ho show mixmg effects unexplainable by the present calculations.