Towards the understanding of 11P1 meson mass spectrum

Based on the meson-meson mixing and Regge trajectory, this paper establishes the mass relations which can describe the mass spectrum of 1^1 P1 meson state. Using these mass relations, it obtains the mass of K1B, hi （1380） and hc（1P） to be 1358.5MeV, 1468 MeV and 3543.9 MeV, respectively. The results are compared with other theoretical results and should be tested by experiments in the future.     

Regarding the 21S0 and 23S1 multiplets

<正>This paper discusses the masses and possible members of 2¹S₀ and 2³S₁ meson multiplets in the framework of meson-meson mixing and Regge phenomenology.For the 2¹S₀ meson nonet,K^*（1460） may be the observed state of the 2¹S₀ isodoublet with a mass of 1400 MeV and the mass ofω（1420） is 1412 MeV.For the 2³S₁ meson nonet,K^*（1410） seems too light to be the 2³S₁ ns member.The fact that the agreement between the present findings and those given by experiments and other different approaches is satisfactory implies that the assignments in this paper may be reasonable.     

Forward K1+ (892) production in K+p → π+Ks0p at 12.7 GeV/c

We have measured 618 K⁺p → π⁺K_S⁰p events at 12.7 GeV/c incident lab momentum, mass range 790 ? m_π⁺Ks⁰ ? 990 MeV and t range 0.01 ? ?t ? 0.60 (GeV/c)². The π⁺K_S⁰ mass spectrum is dominated by the K¹⁺ (892) resonance and a Breit-Wigner fit yields a mass m = 893.5 ± 1.1 MeV and a width Γ = 33.2 ± 4.1 MeV which is much narrower than measured hitherto. The t distribution of K¹⁺ (892) events shows a dip in the forward direction and an exponential fall off thereafter, consistent with dominance of helicity flip amplitudes. The spin density matrix is almost saturated by ρ₁₁ and ρ_1?1 which are very close to their maximum allowed value of $\text{1}\text{2}$ throughout the measured t range except in the very forward direction where ρ₀₀ and Re ρ₁₀ deviate from zero. Natural parity exchanges, therefore, dominate with unnatural parity exchanges being restricted to a small region in the forward direction. A Regge pole analysis of the differential cross sections of the present measurement in conjunction with previously measured total cross sections supports the f-coupled-pomeron hypothesis.     

Transition densities between the 01+, 21+, 41+, 02+, 22+, 11− and 31− states in 12C derived from the three-alpha resonating-group wave functions

All the multipole transition densities between the seven T = 0 states in ¹²C are calculated with the use of the microscopic 3α resonating-group wave functions which are obtained by dynamically solving the 3α relative motion with the total antisymmetrization taken into account exactly. The observed elastic and inelastic electron scattering form factors for the transition to the 2₁⁺, 4₁⁺, 0₂⁺, 1₁^?and 3₁^? states are well reproduced with no additional effective charge. The existence of a deformed intrinsic state for the 0₁⁺, 2₁⁺and 4₁⁺states is deduced by the analysis of the transition densities between them which are derived by the weak-coupling-type 3α wave functions; the intrinsic density distribution is illustrated. The monopole density distribution of the 0₂⁺, 2₂⁺ and 1₁^?, states is found to be much longer ranged than that of the 0₁⁺, 2₁⁺ and 4₁⁺ states; the 3₁^? state case is intermediate. On the basis of the transition densities between the 0₁⁺, 2₁⁺, 0₂⁺ and 2₂⁺ states, analysis is made of the transition between the shell-like states and the molecule-like states with a large spatial-structure change. Specific, effective nucleon-nucleon interactions are folded into the transition densities here obtained. The evident dependence of the radial shape of the folded nucleon-¹²C form factors on the choice of the interactions and the multi-step form factors for the excitation of the 0₂⁺, 1₁^? and 3₁^? states are discussed.     

氢同位素氚水T2O(X1A1)的解析势能函数

获得T₂O(X¹A₁)解析势能函数的主要困难在于Born-Oppenheimer近似下T₂O(X¹A₁)与H₂O(X¹A₁)势能函数的不可区分性.然而,在Born-Oppenheimer近似下,分子势能函数实际上是键长、键角这些 关键词： 2O(X¹A₁)')" href="#">T₂O(X¹A₁) 同位素效应 解析势能函数     

Specific mass shift of potassium 5P1/2 state

We have measured the isotope shift between ⁴¹K and ³⁹K in the 4s_1/2 → 5p_1/2 transition at 405 nm using saturation spectroscopy. Our measured isotope shift is 456.1 ± 0.8 MHz, implying a residual isotope shift (sum of specific mass shift and field shift) of −52.7 ± 0.8 MHz. We deduce a specific mass shift of −40 ± 5 MHz, which would imply that the 5p_1/2 state has a considerably larger specific mass shift than the 4p_1/2 state. We have in addition measured the 5p_1/2 hyperfine splitting for ⁴¹K.     

Ba原子6s6p1P1←6s6s1S0跃迁的光腔衰荡光谱

建立了一套光腔衰荡原子束吸收光谱测量装置,并对Ba原子的6s6p¹P₁←6s6s¹S₀吸收谱线用光腔衰荡光谱方法进行了测量,得到了Ba原子在553.548nm不同温度下的吸收谱线线型.实验结果表明,该装置测量吸收灵敏度达到6×10^-7. 关键词： 光腔衰荡 吸收光谱 Ba原子     

Coherent Raman spectra of the ν1 mode of BF3 and BF3

High resolution (0.001 cm⁻¹) coherent anti-Stokes Raman spectroscopy (CARS) was used to directly examine the ν₁ symmetric stretching mode of the planar symmetric D_3h molecules ¹⁰BF₃ and ¹¹BF₃. Simulations of the spectra were done using ν₁ rovibrational parameters deduced from published infrared hot-band and difference-band studies and the close similarity to the observed CARS spectra confirms the validity of the infrared constants. No significant perturbations by Fermi resonance or Coriolis interactions with nearby states are observed, in marked contrast to the case of sulfur trioxide, a similar D_3h molecule recently studied. In the harmonic approximation, the ¹⁰BF₃ and ¹¹BF₃ν₁ Q-branches would be identical since the isotopic substitution is at the center of mass but, interestingly, the ν₁ stretching frequency for ¹¹BF₃ is found to be 0.198 cm⁻¹higher than for the lighter ¹⁰BF₃ isotopomer. This counterintuitive result is reproduced almost exactly (0.200 cm⁻¹) by ab initio calculations (B3LYP/cc-pVTZ) that included evaluation of cubic and quartic force constants and x_ij anharmonicity constants. The ab initio computations also predict to within 1% the ΔB, ΔC changes in the rotational constants in going from the ground state to the v₁ = 1 vibrational level. The results illustrate nicely the complementary interplay of modern infrared, Raman, and ab initio methods in obtaining and analyzing rovibrational spectra.     

钙钛矿型晶体A(B1/31B2/32)O3中的有序-无序相变

本文利用原子集团变分方法,讨论了A⁺²(B_1/3⁺²B_2/3⁺⁵)O₃系统中有序-无序相变,指出在此系统中相互作用能参数对形成(B_2/3⁺²B_1/3⁺⁵)_1/2:B_1/2⁺⁵=1:1的混合型有序畴和B_{1/3关键词：}     

Analytical potential energy function for the electronic states 2^∏1/2 and 2^∏3/2 of O^x2 （x=＋1, -1）

The splitting of potential energy levels for ground state X^2∏g of O^x2 （x = ＋1,-1） under spin-orbit coupling （SOC） has been calculated by using the spin-orbit （SO） multi-configuration quasi-degenerate perturbation theory （SO-MCQDPT）. Their Murrell-Sorbie （M S） potential functions are gained, and then the spectroscopic constants for electronic states 2^∏1/2 and 2^∏3/2 are derived from the M S function. The vertical excitation energies for O^x2 （x = ＋1,-1） are v[O2＋1^（2∏3/2→X^2∏1/2）] =195.652cm^-1, and v[O2^-1（2^∏1/2 →X^2∏3/2）] =182.568cm^-1, respectively. All the spectroscopic data for electronic states 2^∏1/2 and 2^∏3/2 are given for the first time.     

Kr2F1 and Kr12 radiative lifetime measurements

Atomic krypton was excited in presence of SF₆ by an intense electron beam. The radiation emitted by the Kr₂F¹(²B₂→ A₁) transition was studied at 430 nm using time resolved spectroscopic techniques. The radiative lifetimes of Kr₂F¹ and of Kr¹₂ were found to be 200 ns and 270 ns respectively.     

Rotational analysis of the ν1, 2ν1 and 5ν1 stretching bands of HGeD3

The high-resolution spectrum of the ν₁=5 stretching overtone of gaseous H⁷⁰GeD₃ has been recorded by an intracavity laser absorption spectrometer based on a vertical external cavity surface emitting laser (VECSEL). The rotational structure of the excited state at 9874.605 cm⁻¹ was found weakly perturbed by unidentified interaction with dark states. Finally, of the 313 lines rotationally assigned, 239 lines were found unperturbed and could be reproduced with a root-mean-square (rms) deviation of 0.012 cm⁻¹. The retrieved set of rotational parameters agrees with the values extrapolated from the previously studied ν₁=6-8 stretching overtones. High-resolution FTIR spectra of the ν₁ and 2ν₁ bands have also been recorded and analyzed. The ν₁=1 level, (ν_eff=2114.15 cm⁻¹) is in anharmonic interaction with a further A₁ symmetry level (ν_eff=2102.39 cm⁻¹). The potential coupling term could be estimated (W_anh=5.6(3) cm⁻¹) and the most probable assignment of the perturber is ν₂+ν₃. Moreover both levels are rotationally perturbed in an irregular fashion. Only a coarse analysis up to J=6 could be performed. The 2ν₁ band reveals irregular perturbations of medium intensity by unknown dark states for almost all K values. Nevertheless the obtained leading rovibrational parameters of the 2ν₁ band for J?6 are in agreement with those of the ν₁=5-8 states.     

1S0 and 3S13D1 nucleon-nucleon potentials in the quark compound bag model

For nucleons interacting via formation of the quark compound bag the resulting potential is written in a general form. Explicit examples of potentials are constructed in the ¹S₀, ³S₁ and ³S₁-³D₁ states fitted to the experimental data at T_L ? 1 GeV. As an outcome the QCB energy levels (dibaryons) and NN admixture in QCB are obtained in good agreement with theoretical predictions.     

Jet Spectroscopy of theD12B1–D01B1Transition of thep-Cyanobenzyl Radical

We have generated thep-cyanobenzyl radical in supersonic free expansion, and measured the vibrationally and rotationally resolved laser induced fluorescence (LIF) excitation spectra and the LIF dispersed spectra from the single vibronic levels (SVL) in the green-blue region. The lowest energy band at 20 738 cm⁻¹with the strongest intensity in the excitation spectrum has been assigned to the 0⁰₀band of the visible spectrum, on the basis of the vibronic structures in the SVL dispersed spectra. Based on the band type of the 0⁰₀band,a-type, determined from the rotationally resolved LIF excitation spectrum, we have definitely assigned the visible band to theD₁2²B₁–D₀1²B₁electronic transition. We have found, on the grounds of the vibrational analysis of the dispersed spectra, that the vibronic structure of the 2²B₁–1²B₁electronic transition of the benzyl type is characterized by totally symmetric fundamental modes, 1, 8a, and 9a.     

The Ã1A1-X̃1A1 two-photon fluorescence excitation spectrum of 1,2-difluorobenzene

The two-photon fluorescence excitation spectrum of 1,2-difluorobenzene was obtained with a tunable dye laser calibrated using a combination of the neon optogalvanic spectrum and etalon fringes. The spectrum consists only of A₁-A₁ bands but the use of linear and circular polarization divides the bands into two types. The 0⁰₀ type retains its intensity in circular polarization and, rotationally, shows little or no zero-rank contribution. The 5¹₀ (or 14¹₀) type loses much of its intensity in circular polarization and, rotationally, shows a large zero-rank contribution. These observations all accord with the trace of the two-photon transition tensor being close to zero for the 0⁰₀ type and large for the 5¹₀ type, the latter type being involved in vibronic interaction which mixes the $\text{A}\text{?}$ and $\text{X}\text{?}$ states. There is strong evidence for Fermi resonance between the 5¹ and 6¹10¹ levels. Parts of the one-photon absorption spectrum have been photographed to aid sequence identification and also to look for the 5¹₀, A₁-A₁ transition. This transition is not observed: nor is there any evidence for intensity stealing by b₂ vibrations.     

Absolute measurement of an atomic cascade rate using a two photon coincidence technique. Application to the 4p21S0 -4s4p 1P1 -4s21S0 cascade of calcium excited by a two photon absorption

The two photon coincidence technique yields an absolute measurement of a cascade decay rate without knowing the detection efficiency of each detector. This method is applied to calcium atoms in an atomic beam excited to the 4p²¹S₀ state, and decaying via the resonant ¹P₁ state; it yields the excitation rate of the upper 4p²¹S₀ level. Since the excitation process (two photon absorption) is controlled, one can compute the excitation rate of the upper level as a function of the transition probabilities in the cascade. The lower transition is well known and we can therefore deduce the transition probability for the 4p²¹S₀ -4s4p ¹P₁, transition which previously had not been accurately determined. The preliminary measurements yield a line strength s = 0.98 ± 0.3 au in good agreement with a recent measurement of the lifetime of the 4p²¹S₀ state.     

Kinetic properties of p-Mg2SixSn1 ? x solid solutions for x < 0.4

The results of a study of Mg₂Si _x Sn_{1 − x} solid solutions (x = 0.25, 0.3, 0.35, 0.4) are reported. The measurements performed cover the Seebeck coefficient, electrical conductivity and the Hall coefficient over broad ranges of temperatures (80–700 K) and carrier concentrations (10¹⁸ to 6 × 10²⁰ cm⁻³). These measurements were used to derive the band structure parameters (band gap, hole mobility, hole effective mass). The effective mass of holes was found to grow strongly with an increase in their concentration.     

Modulation of the A1 resonance

A model is outlined for isolating the effects of final state interactions in an amplitude leading to three final pions. The method accounts for rearrangements among ?π and ?π states, producing a factor-of-2 fluctuation in the 1⁺ intensity below the A₁ mass. It follows that this effect should cause a modulation of the A₁ resonance.     

Room temperature magnetoresistance in Ln2/3A1/3MnO3 manganites

The investigation of the manganites La_2/3−xPr_xSr_1/3MnO₃, La_2/3Sr_1/3−xCa_xMnO₃ and La_2/3+xCa_1/3−2xAg_xMnO₃, which all exhibit Mn³⁺:Mn⁴⁺=2, shows that it is possible to reach high magnetoresistance at room temperature, up to 21% under 1.2 T. These materials are compared to La_5/6Ag_1/6MnO₃ which corresponds to the same Mn³⁺:Mn⁴⁺ ratio and exhibits a magnetoresistance of 25% in this field. An interesting feature deals with the value of the insulator-metal transition temperature T_IM, often higher than T_C, especially for Ag-based compounds. It is suggested that the latter results either from a better oxygenation of the surface of the grains or from a migration of silver toward the surface.     

Spectroscopic analysis of the d1Σ+→a1Σ+ and d1Σ+→b1Π green band systems of XeO

A comprehensive high resolution spectroscopic analysis has been made on the XeO green bands photographed in emission from an RF discharge source. Rotation-vibration constants derived from the analysis of the spectrum of the isotopically enriched species ¹²⁹Xe¹⁶O and ¹²⁹Xe¹⁸O were used to give RKR potential curves for the d¹Σ⁺ and b¹Π states. The bond distances and dissociation energies of the d¹Σ⁺ and b¹Π states were respectively found to be $\text{r}{}_{\mathrm{e}}\text{= 2.852 ± 0.002}\text{A}\text{?}$, D_e = 693 ± 10 cm^?1 and $\text{r}{}_{\mathrm{e}}\text{= 2.548 ± 0.002}\text{A}\text{?}$, D_e = 461 ± 10 cm^?1. For the a¹Σ⁺ state it was not possible to establish a unique vibrational numbering or to construct an RKR potential curve, since observed bands of the d¹Σ⁺→a¹Σ⁺ system involve only high vibrational levels of the a¹Σ⁺ state, which are severely predissociated. The observations are consistent with a fairly deep well, in agreement with the latest ab initio calculations which give a well depth of 0.7 eV.