Deexcitation of K π = 0 2+ , 0 3+ , and 21/+ levels by M 1 transitions in nonspherical even-even nuclei

The signs of the experimental values of the multipole-mixture parameters δ are compared with the signs of ℛ = Σa _i μ _i for (2⁺0₂−2⁺0₁) and (2⁺0₃−2⁺0₁) transitions and with the signs of = Σa _i [(μ _i + μ _kν ) or (μ _kπ − 1/2)] for (2⁺2₁−2⁺0₁) transitions in nonspherical even-even nuclei, where a _i is the contribution of the ith pair of quasiparticles to the wave function for 2⁺0₂, 2⁺0₃, and 2⁺2₁ single-phonon states according to the quasiparticle-phonon model and μ is the magnetic moment for the corresponding Nilsson state. Original Russian Text ? A.M. Demidov, L.I. Govor, V.A. Kurkin, I.V. Mikhailov, 2009, published in Yadernaya Fizika, 2009, Vol. 72, No. 2, pp. 228–235.     

Calculation of spectroscopic constants and radiative parameters for A1Σ u+ -X1Σ g+ and B1Πu-X1Σ g+ electronic transitions of sodium dimer

Vibrational, rotational, and centrifugal spectroscopic constants and radiative parameters, i.e., the Einstein coefficients, oscillator strengths, and wave numbers for vibrational transitions in electronic systems of bands A ¹Σ _u ⁺-X ¹Σ _g ⁺ (0 ≤ v′ ≤ 25; 0 ≤ v″ ≤ 44), B ¹Π _u -X ¹Σ _g ⁺ (0 ≤ v′ ≤ 29; 0 ≤ v″ ≤ 47), and the radiative lifetimes for the vibrational levels of excited states of the sodium dimer, are calculated. The calculations are carried out based on semiempirical potential curves constructed in this study. The calculated spectroscopic constants and radiative lifetimes are compared to the experimental values.     

Confrontation of nucleus deformation and multipole mixture parameters in (2+0 n ?2+01) transitions with rotational band structure for K π = 0 2+ and 0 3+

The difference of the energies of levels Δ _n = E _lev(2⁺0 _n ) − E _lev(0⁺0 _n ) at n = 1, 2, and 3 and the multipole-mixture parameter δ for (2⁺0₂−2⁺0₁) and (2⁺0₃−2⁺0₁) transitions are contrasted against the structure of the K ^π = 0₂⁺ and 0₃⁺ rotational bands that was calculated on the basis of the quasiparticle-phonon model. The values of (Δ₂ − Δ₁), (Δ₃ − Δ₁), and (Δ₂ − Δ₃) are found to correlate with the sign of the parameter δ and with the calculated structure of the K ^π = 0₂⁺ and 0₃⁺ bands. Original Russian Text ? A.M. Demidov, L.I. Govor, V.A. Kurkin, I.V. Mikhailov, 2009, published in Yadernaya Fizika, 2009, Vol. 72, No. 2, pp. 236–240.     

硼羰基络合物正离子B(CO)3+和B2(CO)4+的红外光解离光谱

利用脉冲激光溅射-超声分子束载带方法制备气相硼羰基络合物正离子. 采用红外光解离光谱研究了B(CO)₃⁺、B(CO)₄⁺ 和B₂(CO)₄⁺的振动光谱. 研究结果表明B(CO)₃⁺具有非常强的B-CO键,无法直接获得其红外光解离光谱. 对B(CO)₄⁺的光解离光谱研究表明该离子是一个B(CO)₃⁺和CO之间弱相互作用络合物. 其中B(CO)₃⁺核具有平面D_3h对称性结构,中心硼具有稳定的8电子组态. B₂(CO)₄⁺具有平面的D_2h对称性结构,其中的B-B键包含一个σ键和半个π键. 自然轨道能量分解分析(EDA-NOCV)表明在B(CO)₃⁺和B₂(CO)₄⁺中的B-CO成键作用中OC→B(σ)要比B→CO(π)反馈作用强.     

Cross section and rate coefficient calculations for electron impact excitation, ionisation and dissociation of the X 1Σg+, c 3Πu, a 3Σ g+, e 3Σu+ and B′1Σu+ states of H2

The weighted total cross section (WTCS) theory has been applied to the electron-H₂ collision to obtain excitation, ionisation and dissociation cross section and rate coefficients of the X ¹S_g⁺^{1}\!\Sigma _{g}^{+}, c ³P_u^{3}\!\Pi _{u}, a ³S_g⁺^{3}\!\Sigma _{g}^{+}, e $^{3}\!\Sigma _{u}^{+}$^{3}\!\Sigma _{u}^{+} and B^{′ 1}S_u⁺^{1}\!\Sigma _{u}^{+} states. Calculation has been performed in the temperature range 1500 K–15000 K. Rate coefficients are calculated from WTCS assuming Maxwellian energy distribution functions for electrons and heavy particles. Thermal equilibrium results are presented and fitting parameters (a, b and c) are given for each reaction rate coefficient: k(θ) = a (θ^b) exp(-c/θ).     

N2��Ƶ�ŵ��������(e,N2+, N+)��PIC-MCģ��

采用PIC-MC自洽模型,模拟了氮气电容性耦合射频放电的微观等离子体过程及带电粒子(e,N2+,N+)的行为。结果表明,离子(N2+,N+)的运动状态滞后瞬时射频电场的变化;在两极附近,N2+具较高密度,但能量较低,N+具较低的密度但能量较高,两者的密度差6倍左右。两种离子轰击射频电极的能量分布变化规律类似,随放电参数变化,离子(N2+,N+)能量变化显著,其密度变化不明显。模拟的电子能量几率分布与测量结果一致。     

Overlapping B3Π0u ← X1Σ g/+ and 1Π1u ← X1Σ g/+ non-radiative characteristic of Br2 vapour in the wavelength region 505–541 nm

The vibronic vapour phase photoacoustic spectrum of Br₂ in the wavelength region 505–541 nm (19796–18480 cm⁻¹) has been recorded using microphone as well as pump-probe method. Discrete vibronic bands superimposed on a monotonically increasing continuum background towards the dissociation limit results from the overlapping B ³Π _0u ^/+ ← X ¹Σ _g ^/+ and ¹Π_1u ← X ¹Σ _g ^/+ electronic transitions. Vibronic bands originating from υ″=0 have been used to estimate the relative rate of non-radiative relaxation as a function of the excited state B ³Π_0u vibrational quantum number υ′. A comparison with the optical absorption spectroscopy of Br₂ leads to the identification of three broad spectral regions between 505 and 541 nm (19796 and 18480 cm⁻¹) on the basis of different non-radiative relaxation processes.     

Lithium ion transport in PVC/PEG 2000 blend polymer electrolytes complexed with LiX (X=ClO 4? , BF 4? , and CF3SO 3? )

This paper describes preparation and characterization of polyvinyl chloride and polyethylene glycol 2000 blend polymer electrolytes with LiX (X=ClO₄⁻, BF₄⁻, and CF₃SO₃⁻) salt by solution casting technique. Ethylene carbonate and propylene carbonate mixture was used as the plasticizers. LiClO₄-based electrolytes exhibited better ionic conduction behavior than other salts. The thermal profiles ascertain the stability of the membranes up to 120°C by differential scanning calorimetry. Complexation and crystallinity were studied through X-ray diffraction measurements. Phase morphological study reveals the porous nature of the polymer electrolyte membranes.     

氨分子在000和201带的选择光离解

本文利用脉冲紫外激光(UV)选择激发氨分子到?¹A″₂电子激发态的两个最低振动能级ν′₂=0和ν′₂=1(ν₂振动),然后检测新生态H原子的飞行谱(TOF),研究了氨分子的光碎片动力学。光谱证实了最近所测的离解能D₀⁰(H-NH₂)=4.645eV;绝大多数生成的NH₂(X²B₁)基处于非振动激发,但是具有围绕a惯性轴的高度转动激发。通过NH₃(?)的ν′₂=1光离解产生的NH₂(X)基具有较高的内部激发,并且显示了在N=K_a转动能级上的反转布居。 关键词：     

Perspectives for the measurement of Ds+ mesons via?the?Ds+ →K+K?π+ channel in the ALICE experiment

Heavy quarks, such as charm, are produced in hard scatterings in the early stages of high energy nucleus-nucleus collisions and are expected to be a powerful tool to investigate the properties of the quark gluon plasma (QGP). The tracking detectors of the ALICE apparatus will allow to track and identify particles in central rapidity range down to low P _t . Among D mesons it would be particularly interesting to measure D _s yield via an exclusive hadronic decay channel because it could help to disentangle different hadronization mechanisms. The possibility of reconstructing the D _s meson through its D _s ⁺→K ⁺ K ⁻ π ⁺ decay channel in the central barrel was studied. The problem considered is characterized by the comparatively low yield of the D _s mesons against the huge amount of combinatorial background. Different kinematic and topological cuts have been studied in order to increase the signal-to-background ratio and the statistical significance. In addition, D _s mesons preferentially decay through intermediate resonant states and this fact can improve the separation of signal from background. Results of cut parameters tuning and values of significance for an analysis performed on simulated data are presented.     

H1+,H2+,H3+和He,Ne,Ar碰撞过程中的巴耳末系Hα,Hβ,Hγ发射

实验利用TN-1710光学多道分析系统(OMA),对H₁⁺,H₂⁺,H₃⁺和He,Ne,Ar碰撞过程中产生的巴耳末系H_α,H_β,H_γ发射进行了测量,入射离子H₁⁺,H₂⁺,H₃⁺的 关键词：     

Quasi-classical trajectory study of the stereodynamics of a Ne+H2+→NeH++H reaction

We have carried out a quasi-classical trajectory calculation for the reaction of Ne + H₂⁺ (v=0, j=1) → NeH⁺ + H on the ground state (1²A') using the LZHH potential energy surface constructed by Lü et al. [Lü S J, Zhang P Y, Han K L and He G Z 2010 J. Chem. Phys. 132 014303]. Differential cross sections at many collision energies indicate that the reaction is dominated by forward-scattering. In addition, the NeH⁺ product shows rotationally hot and vibrationally cold distributions. Stereodynamical results indicate that the products are strongly polarized in the direction perpendicular to the scattering plane and that the products rotate mainly in planes parallel to the scattering plane.     

H3+立体化学结构的测量

本文报道了用“库仑爆炸”技术对H₃⁺分子离子的立体化学结构测量。实验表明:H₃⁺的结构为正三角形,其最可几质子间距的平均值为0.98±0.03?。文中还介绍了我们的高分辨实验装置。 关键词：     

Vibrational analysis of Fourier transform spectrum of the A3Π0-X1Σ+ and B3Π1-X1Σ+ transitions of indium monobromide

The emission spectrum of InBr molecule has been recorded in the region 350–400 nm on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.06 cm⁻¹ using microwave excitation technique. About 61 violet degraded and single headed bands have been recorded and are classified into two band systems, viz. A³Π₀-X¹Σ⁺ and B³Π₁-X¹Σ⁺. A few new bands have been observed and are fitted in the vibrational schemes of the two systems. Revised vibrational constants have been determined. The vibrational assignments have been confirmed by observing isotope effect due to InBr⁸¹ in the 30 bands of the A³Π₀-X¹Σ⁺ system and 19 bands of the B³Π₁-X¹Σ⁺ system. The analysis is further supported by calculating the Franck-Condon factor for InBr⁷⁹ and InBr⁸¹ molecules. The following vibrational constants (in cm⁻¹) have been determined from the analysis:      

纳米NaY1-x-yF4：Yby3+, Tmx3+材料的上转换光学特性

用水热法合成了NaY_1-x-yF₄:Yb_y³⁺,Tm_x³⁺上转换纳米粒子材料。实验发现,样品的粒径多数在100nm以内;当加热温度180℃、反应时间120min、稀土离子Tm³⁺的摩尔分数为0.04%时,所制备的纳米材料在980nm半导体激光激发下,其主要上转换发光的辐射峰值位于476.54nm处。     

Na2CaSiO4∶RE3+(RE=Ce3+,Tb3+,Eu3+) 的制备及发光特性

采用高温固相法,合成了三价稀土离子(RE³⁺=Ce³⁺, Tb³⁺, Eu³⁺)掺杂的Na₂CaSiO₄(NCS)系列样品,并研究了其在紫外光激发下的发光特性。研究结果表明,Ce³⁺、Tb³⁺ 和Eu³⁺掺杂的NSC系列样品在紫外光源激发下,均呈现其特征发射,随着掺杂浓度的提高,发射强度逐渐增大。Ce³⁺、Tb³⁺和Eu³⁺的最佳摩尔分数分别为0.13、0.13和0.12,相应的色坐标分别计算为(0.17, 0.17)、(0.34, 0.58)和(0.66, 0.34),分别为很好的蓝光、绿光和红光。继续增加稀土离子的含量,发射强度降低。     

发光颜色可调的硅酸盐长余辉发光材料 Ba4(Si3O8)2∶Eu2+,Ce3+,Dy3+

在还原气氛下利用高温固相法制备了Ba_3.982-x(Si₃O₈)₂∶0.008Eu²⁺,xCe³⁺,0.01Dy³⁺系列样品。光谱分析表明,Ce³⁺进入到晶格中将取代不同Ba²⁺格位从而形成不同的发光中心。通过Ce³⁺→Eu²⁺的能量传递,得到了一系列发光颜色可调、余辉颜色为绿色的长余辉发光材料。Ce³⁺的掺入可以增大样品的余辉强度但是同时缩短了样品的余辉时间。热释光谱的分析表明,Ce³⁺的掺入可以同时增加浅陷阱T₁和深陷阱T₃的数量,深陷阱对载流子的再捕获效应导致了样品余辉强度的增大和余辉时间的缩短。     

纳米YAG∶Ce3+, Mn+(Mn+=Ca2+, Gd3+)荧光粉的结构与发光性能

当前商用白光LED器件中YAG∶Ce3+荧光粉的单一黄光发射,导致其缺乏红光限制了器件的应用和发展,在YAG∶Ce3+中掺杂其他离子是解决该问题的有效途径之一。采用溶胶凝胶法制备了系列单掺Ce3+,Ca2+和Gd3+的YAG纳米荧光粉。研究了离子掺杂量对荧光粉的物相、结构、形貌、粒度、发光性能及量子效率的影响,分析了发光机理。结果表明：制备的纳米荧光粉粒径为100～200 nm。Ce3+和Gd3+掺杂时均得到YAG纯相,但晶体结构膨胀,晶面衍射峰向小角度方向移动。样品结晶度随Ce3+和Ca2+(<0.025 mol)掺杂量增大变化不明显,随Gd3+则呈现逐步降低趋势。三种离子掺杂量增大时,Ce3+的晶格能上升,5d能级晶体场劈裂加剧;Gd系列荧光粉激发和发射光谱随掺杂量的增大发生红移,Ce和Ca系列则因掺杂量小表现不明显。荧光粉发光强度随Ce3+掺杂量上升先增大后减小,最佳掺杂量为0.06 mol;随Gd3+掺杂量增加逐步降低;随Ca2+掺杂量增大则急剧下降,0.03 mol掺杂量时荧光强度几乎为零,YAG晶体结构破坏,生成YAM和YAP相。研究的开展,将对后续纳米YAG荧光粉及其相关功能材料的进一步开发使用提供一定的理论依据和实践参考。     

荧光粉CaWO4：Eu3+中WO42-与Eu3+间的能量转递

通过高温固相法分别制备了CaWO₄和CaWO₄:1%Eu³⁺ 样品. 测量了样品不同温度(10–300 K)的荧光光谱、荧光衰减曲线和 时间分辨荧光光谱. 样品的荧光光谱表明: 在240 nm紫外光激发下, 两个样品在430 nm处都展现出来源于WO₄^2-的蓝色发射; 样品CaWO₄:Eu³⁺的Eu³⁺(⁵D₀→⁷F_{1, 2, 3,4})的特征发射则归属于WO₄^2-到Eu³⁺ 间的能量传递.由样品室温(300K)荧光衰减曲线发现: 纯CaWO₄的荧光寿命为8.85μs,Eu³⁺掺杂之后WO₄^2-的荧光寿命缩短至6.27μs,这从另一方面证明了WO₄^2-与Eu³⁺间能量传递的存在. 由荧光寿命得到T=300K时, CaWO₄: 1%Eu³⁺中WO₄^2-与Eu³⁺间的能量传递效率(η_ET)为29.2%, 能量传递速率(ω_ET)为4.65×10⁴ s^-1.通过时间分辨荧光光谱, 获得了从WO₄^2-到Eu³⁺之间的能量传递的时间演变过程,当温度由10 K增加到300 K时, 能量传递出现的时间单调变小. 测试了不同温度(10–300 K)对CaWO₄:Eu³⁺的荧光寿命的影响, 发现在10–50K时,Eu³⁺的荧光寿命增加, 但温度超过50K时发生猝灭, 荧光寿命开始下降; WO₄^2-的荧光寿命则是随着温度的升高逐渐缩短. 关键词： 能量传递 红色荧光粉 温度依赖 4：Eu³⁺')" href="#">CaWO₄：Eu³⁺     

NaZnLa(PO4)2中Ce3+和Tb3+的发光

采用高温固相反应合成了NaZnLa(PO₄)₂中掺杂Ce³⁺、Tb³⁺的荧光体,对其晶体结构、发光行为进行了研究,并尝试对NaZnLa(PO₄)₂:Ce,Tb荧光体进行调制。NaZnLa(PO₄)₂是LaPO₄的同构物,为单斜晶系独居石结构,从XRD谱数据得到NaZnLa(PO₄)₂基质的晶胞参数为a=0.6823nm,b=0.7045nm,c=0.6497nm,β=1039°,v=0.303nm³,其晶胞参数与单斜LaPO₄的晶胞参数相似。在NaZnLa(PO₄)₂:Ce,Tb荧光体中,Ce³⁺对Tb³⁺有良好的敏化作用,掺杂适量的BO₃^3-、Al³⁺、Dy³⁺,可以增强发光亮度。