2+1维SU(2)规范理论的胶球质量

本文对具有严格基态解的格点规范哈密顿量采用变分法,计算了2+1维SU(2)规范群的胶球质量.得到在0≤1/g²≤7范围内,标度行为是am=2.28g²,与弱耦合展开结果一致.     

Sc+18离子的跃迁能和振子强度

用全实加关联方法计算了Sc⁺¹⁸离子1s²2s--1s²np (2≤n≤9) 和1s²2p--1s²nd (3≤n ≤9)的跃迁能和振子强度。1s²np和1s²nd 态的精细结构劈裂通过计算自旋-轨道及自旋-其他轨道相互作用算符的期待值加以确定。还得到了这两个里德堡系列的量子亏损（作为能量的函数）。依据三种规范的振子强度公式得到的计算结果相当好的一致。将这些计算结果与量子亏损理论相结合，进一步得到电离阈附近的分立态-分立态跃迁的振子强度和分立态-连续态跃迁的振子强度密度。     

2+1维SU(2)格点胶球质量的变分计算

本文对具有严格基态解和正确经典连续极限的格点规范哈密顿量,采用变分法,计算了2+1维SU(2)规范群的胶球质量,得到在1.3≤1/g²≤7范围内,标度行为是am=2.28g²,这与弱耦合展开及另一没有正确连续极限的哈密顿量的结果一致.     

Theoretical study on 2s2p6np Rydberg states of Cu19+ ion

We report on the calculations of transition wavelengths and weighted oscillator strengths for 2s²2p⁶-2s2p⁶ⁿp (4 ≤ n ≤ 20) electric dipole (E1) transitions of Cu¹⁹⁺ ion. The flexible atomic code (FAC) has been adopted for the calculations. Comparisons are made with the experimental data available, showing that the present results for 4 ≤ n ≤ 6 are more accurate than the previous calculated values. Furthermore, combining the quantum defect theory (QDT) with the transition energies of 2s²2p⁶-2s2p⁶np, the quantum defects for 2s2p⁶np Rydberg series of Cu¹⁹⁺ ion are determined. In addition, the energies of any highly excited states (n > 20) for this series can be reliably predicted using the QDT and the given quantum defects. The ionization energies for Cu¹⁹⁺ and Cu²⁰⁺ ions are also calculated and they excellently accord with previous experimental and calculated values.     

NCl(a1Δ)/I（2P3/2）传能体系的实验研究

 利用微波放电Cl₂/He等离子体作为Cl源，对反应NCl(a¹Δ) + I(²P_3/2)→NCl(X³Σ) + I(²P_1/2)进行了实验研究，得到了较大的I(²P_1/2)自发辐射荧光信号，检测到NCl(a¹Δ，b¹Σ)自发辐射荧光光谱在存在少量I(²P_1/2)下发生的显著变化，其中NCl(a¹Δ)自发辐射荧光信号降低，同时由于I(²P_1/2)的作用，NCl(b¹Σ)自发辐射荧光信号大幅度增加。在考察各反应气体流量对I(²P_1/2)自发辐射荧光信号的影响时发现，在本次实验条件下，各种气体的最佳流量：He为1～4mmol/s, I₂为0.01～0.03mmol/s, Cl₂为1.0mmol/s左右,而HN₃流量略大于Cl₂流量时信号升高幅度开始变缓，约为Cl₂流量的两倍时信号不再有显著的变化。     

OCS+分子经由B2∑+←X2∏跃迁的光解离谱

制备出确定旋轨态的OCS⁺(X²∏)离子,在260～325 nm波长范围内研究了OCS^{+经由B2∑+←X2∏_3/2(000)和B2∑+←X2∏_1/2(000,001)跃迁的分质量光解离谱．由光解离谱得到OCS+(B2∑+)电子态的光谱常数υ1(CS stretch)=828.9(810.4) cm-1,υ2(bend)=491.3 cm-1和υ3(CO stretch)=1887.2 cm-1．在B2∑+←X2∏跃迁谱中只能观察到B2∑+(010)←X2∏_1/2(000)跃迁的谱峰, 而观察不到B2∑+←X2∏_3/2(000)跃迁的谱峰． 用X2∏电子态的(000)2∏_1/2和(010)2∑+_1/2电子振动能级之间的K耦合解释了这种B2∑+的υ2弯曲振动模的激发对X2∏电子态的旋轨分裂分量(Ω=1/2,3/2)的相关性}     

2+1维SU(2)群胶球质量的MC计算

本文对具有严格基态解的格点规范哈密顿量,给合变分法和Monte Carlo方法,在18²格点上,计算了2+1维SU(2)规范群的正二十面体分立点群的胶球质量,在0<1/g²范围内,得到与SU(2)群的解析变分法^[3]一致的结果.验证了质量隙的标度行为是am=2.3g².     

模拟核素固化体Gd2Zr2-xCexO7(0≤ x≤ 2.0)的物相及化学稳定性研究

为研究钆锆烧绿石固化Pu(Ⅳ)的相变化情况及化学稳定性, 以Gd₂O₃, ZrO₂为原料, Ce(Ⅳ)作为Pu(Ⅳ)的模拟替代物质, 采用冷压热烧结的方法制备出Gd₂Zr_2-xCe_xO₇(0≤ x≤ 2.0)系列样品. 分别在40 °C和70 °C的合成海水中, 对固化体的长期浸出性能进行研究. 借助粉末X射线衍射仪对所制备样品的物相信息进行收集, 利用等离子体质谱仪对固化体的浸出浓度数据进行分析. 研究结果表明: 当x ≤0.08时, 固化体保持为烧绿石相; 当x>0.08时, 固化体转变为具有缺陷的萤石型结构相. 固化体中Gd³⁺, Zr⁴⁺和Ce⁴⁺在合成海水中, 随着浸泡时间的延长浸出浓度逐渐上升, 70 °C下的浸出浓度高于40 °C下的浸出浓度. 在42 d时, 固化体中Gd³⁺的最大浸出浓度在0.032 μg·ml^-1以下, Zr⁴⁺的最大浸出浓度在0.003 μg·ml^-1以下; Ce⁴⁺的最大浸出浓度在0.032 μg·ml^-1以下.     

THE 82S1/2→62D EXCITATION TRANSFER OF RUBIDIUM ATOMS INDUCED BY COLLISIONS WITH GROUND-STATE RUBIDIUM AND HYDROGEN MOLECULES

The processes of excitation transfer from the 8²S_1/2 state to the 6²D state of rubidium in Rb(8²S_1/2)-Rb(5²S_1/2) and Rb(8²S_1/2)-H₂ collisions have been studied experimentally. During irradiating the Rb vapor, mixed with H₂, by two light beams for selective stepwise excitation, the Rb 8²S_1/2→5²P_3/2 direct fluorescence and the Rb 6²D_3/2→5²P_1/2 sensitized fluorescence have been measured as a function of H₂ gas pressure. The measurements yielded the cross-sections σ(8²S_1/2→6²D) and σ^*(8²S_1/2→6²D) of Rb 8²S_1/2→6²D excitation tranfer induced by collisions with 5²S_1/2 atom and H₂ molecules respectively. The results are discussed in detail.     

THE 82S1/2→62D EXCITATION TRANSFER OF RUBIDIUM ATOMS INDUCED BY COLLISIONS WITH GROUND-STATE RUBIDIUM AND HYDROGEN MOLECULES

The processes of excitation transfer from the 8²S_1/2 state to the 6²D state of rubidium in Rb(8²S_1/2)-Rb(5²S_1/2) and Rb(8²S_1/2)-H₂ collisions have been studied experimentally. During irradiating the Rb vapor, mixed with H₂, by two light beams for selective stepwise excitation, the Rb 8²S_1/2→5²P_3/2 direct fluorescence and the Rb 6²D_3/2→5²P_1/2 sensitized fluorescence have been measured as a function of H₂ gas pressure. The measurements yielded the cross-sections σ(8²S_1/2→6²D) and σ^*(8²S_1/2→6²D) of Rb 8²S_1/2→6²D excitation tranfer induced by collisions with 5²S_1/2 atom and H₂ molecules respectively. The results are discussed in detail.     

Study of the Absorption Characteristics of Transitions in the HOT 2υ2–υ2 Band of the 34SO2 Molecule

Russian Physics Journal - The absorption coefficient of the rovibrational 2υ2–υ2 band of the 34SO2 molecule localized in the region 350–850 cm–1 is studied for the first...     

SDW in the 2D Compound CuFeTe2

In a previous work (ICAME'97) we presented the Mössbauer results for a non-stoichiometric sample of the quasi-two-dimensional (2D) dichalcogenide CuFeTe₂, where a Spin Density Wave (SDW) ground state with T _SDW=256±15 K was proposed. Here we report the study of the magnetic and electric properties determined by magnetic susceptibility, Mössbauer spectroscopy and resistance measurements, of an almost stoichiometric sample prepared by the vertical Bridgman growth technique. The SDW behavior is supported by the results obtained by the following different techniques: Magnetic susceptibility: A magnetic transition is observed at T _SDW=308 K with a Pauli paramagnetic behavior above this temperature. Mössbauer effect: The shape of the spectra and the thermal evolution of the hyperfine field are characteristic of the SDW's in quasi-2D systems. Electrical resistance: There is a metal–semiconductor transition along the layers as the temperature decreases indicating the opening of a gap at the Fermi level.     

Quantum critical behaviour in the CePd2Si2/CeNi2Ge2 system

We have explored the vicinity of the antiferromagnetic quantum critical point in the related heavy fermion metals CePd₂Si₂ and CeNi₂Ge₂ as a function of hydrostatic pressure. The normal state resistivity of the antiferromagnet CePd2Si2 near the critical pressure, at which magnetic order disappears, varies as ρ ～ T^χ(1:1 < χ < 1:4) over nearly two orders of magnitude in temperature up to about 30 K. This anomalous form for the resistivity appears to defy not only Fermi-liquid theory, but also simple phenomenological models for the effect of spin fluctuations close to a quantum critical point. An analogous unconventional behaviour is observed in the ambient pressure resistivity of the electronically and structurally equivalent, non-magnetic metal CeNi₂Ge₂. At pressures above 15 kbar, a new and unexpected superconducting transition appears in CeNi₂Ge₂ below 220 mK, which rises to higher temperatures with increasing pressure, reaching 400 mK at 26 kbar.     

Vibrational–Rotational Analysis of the Hot 2ν2–ν2 Band of the 15NH2D and 15NHD2 Molecules

Optics and Spectroscopy - High-resolution spectra of the $$2{{\nu }_{2}}{-} {{\nu }_{2}}$$ hot band of the 15NH2D and 15NHD2 molecules are investigated for the first time. The analysis is carried...     

Accumulating evidence for the two-step magnetic ordering in the borocarbides DyNi2B2C and DyCo2B2C

Accumulating evidence for a two-step magnetic ordering in the borocarbide DyNi₂B₂C is summarized, including earlier overlooked evidence for the initial magnetic transition and a recent magnetization study of polycrystalline samples. The two-step ordering involves initial two-dimensional ferromagnetic ordering in the DyC (basal) planes at T_N (=16.3 K), gradual build-up of the three-dimensional (3D) alternate stacking of ferromagnetic planes, and a final 3D ordering in the AF–I-related structure at a lower temperature T_o (=10.4 K), depicting a first-order transition. Supporting evidence for the two-step magnetic ordering in DyNi₂B₂C comes from point-contact spectroscopy measurements in the normal state for DyNi₂B₂C–Ag contact, and from similar behaviour of PrNi₂B₂C and (Pr_0.91Dy_0.09)Ni₂B₂C. In the isostructural borocarbide DyCo₂B₂C the two magnetic transitions (at 7.8 and 2.6 K) deduced from the specific-heat measurements are also attributed to a two-step magnetic ordering.     

Zeeman effects in the visible 2B2 ← 2A1 system of NO2

The Zeeman effect facilitates certain rotational assignments in bands of the ${}^2\text{B}{}_2\text{-}{}^2\text{A}{}_1$ electronic system of NO₂. A partial analysis of two bands of this system is reported.