Relativistic calculations of 3s2 1S0-3s3p 1P1 and 3s2 1S0-3s3p 3P1,2 transition probabilities in the Mg isoelectronic sequence

Using the multi-configuration Dirac-Fock self-consistent field method and the relativistic configuration-interaction method,calculations of transition energies,oscillator strengths and rates are performed for the 3s 2 1 S 0-3s3p 1 P 1 spinallowed transition,3s 2 1 S 0-3s3p 3 P 1,2 intercombination and magnetic quadrupole transition in the Mg isoelectronic sequence(Mg I,Al II,Si III,P IV and S V).Electron correlations are treated adequately,including intravalence electron correlations.The influence of the Breit interaction on oscillator strengths and transition energies are investigated.Quantum electrodynamics corrections are added as corrections.The calculation results are found to be in good agreement with the experimental data and other theoretical calculations.     

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     

Charmonium-the 1P1 state

Based on a model which gives agreement with the observed hyperfine and fine splitting of the charmonium states, we predict the mass of ¹p₁ to be 3372 MeV, substantially lower than any previous predicted values. We have also estimated branching ratios and decay rates for the production of this state via channels which become accessible because of its low mass.     

Atomic fluorescence under monochromatic excitation: A level crossing experiment on the 6s6p 1P1 level of Ba I

A level crossing experiment on the 6s 6p ¹P₁ level of Ba I was performed using a narrow-band tunable dye laser and a strongly collimated atomic beam. The observed linewidth of the Hanle signal was minimally 45% of the width obtained with broad-band excitation.     

Determination of the lifetime of the mercury 63P1 state

A pulsed tunable dye laser was used for a high resolution experimental study of mercury fluorescence from the 6³P₁ state. The output of the dye laser was frequency doubled into the 253.7 nm region using a potassium penta-borate crystal. Exponential decays were observed for each of the five individual components of the hyperfine structure separately and the effects of the trapping of resonance radiation on the observed lifetime of the 6³P₁ state of mercury were investigated for each resolvable component. Within experimental error, the natural radiative lifetime of the 6³P₁ state was found to be independent of the hyperfine component irradiated and a value of 122±2 nsec was obtained, consistent with results found by other methods.     

钪原子的自电离里德伯能级3d4s(1D2)nf2 D3/2,3d4s(1D2)nf2 F5/2和3d4s(1D2)np2 D3/2<

在多通道量子亏损理论框架下,利用相对论多通道理论,分别在冻结实近似和考虑偶极极化下计算钪原子的J^π=(3/2)^-,(5/2)^-的三个收敛于 3d4s(¹D₂)的自电离里德伯系列的能级.对3d4s(¹D₂)np²D_3/2和3d4s(^{1 关键词： 相对论多通道理论 多通道量子亏损理论 电子-电子关联 自电离里德伯系列}     

New ab initio Potential Energy Surfaces for Cl(2P3/2, 2P1/2)+H2 Reaction

采用多参考组态相互作用的计算方法和很大的基组构造了Cl+H₂反应体系的一组新的三维从头算势能面. 该势能面包含Cl+H₂体系的能量最低的三个绝热态,并在非绝热近似下转化为四个非绝热势能面. 另外,旋轨耦合矩阵元也基于Breit-Pauli Hamil-tonian计算得到. 对角化这四个非绝热势能和两个旋轨耦合矩阵元组成的全耦合Hamiltonian,得到了三个考虑旋轨耦合后的绝热势能面.基于这组新势能面的非绝热动力学计算结果与最新的实验符合得很好,很好地解释了     

Pressure broadening studies on the 33D1-2 3P0 helium line by saturated-absorption techniques

Broadening and shift measurements on the 3³D₁?2³P₀ component of the helium line at λ=587.5 nm are reported. The saturated-absorption method is used. Measurements are performed at room temperature and at liquid nitrogen temperature. Homogeneous broadening constants are deduced from an analysis taking into account the effect of weak velocity-changing collisions. Broadening and shift constants are interpreted in term of a Lennard-Jones interaction potential. The very small shifts observed show the predominance of the repulsive core effect in the interaction potential.     

Investigation of the HFS in the 6s6p1P1 state of 173Yb(I) LC and AC spectroscopy

The hfs of the 6¹P₁ state of ¹⁷³Yb has been investigated by level-crossing and anticrossing spectroscopy. From an optimal fit of experimental and calculated signal curves we get the hfs coupling constants: A = 58.45(80) MHz, B = 589.6(13.0) MHz.     

Lifetimes of bound states in 15O

The lifetime values of 8.2 ± 1.0, > 3000, < 2.5, 16.0 ± 2.5 and 750 ± 200 fs for the first, second, third, fifth and sixth bound states in ¹⁵O, at 5183, 5241, 6176, 6859 and 7276 keV, respectively, were determined with the DSA method through the ¹⁴N(p, γ)¹⁵O reaction. The experimental correction factors of the nuclear and electronic stopping powers were used in the DSA analysis. In the calculations the Monte Carlo method was employed. The transition strengths are discussed in terms of shell-model calculations.     

Lifetimes of low-lying states in 19F

Lifetimes of low-lying states in ¹⁹F were measured using the Doppler-shift attenuation method through the ¹⁵N(α, γ)¹⁹F reaction. Values of τ_m = 3700 ± 700 fs (1.35 MeV), 140 ± 15 (1.46), 19 ± 7 (4.00) and 63 ± 19 (4.03) were obtained for the lowest $\text{5}\text{2}{}^{\mathrm{?}}$, $\text{3}\text{2}{}^{\mathrm{?}}$, $\text{7}\text{2}{}^{\mathrm{?}}$ and $\text{9}\text{2}{}^{\mathrm{?}}$ members, respectively, of the $\text{K}{}^{\mathrm{\pi }}\text{=}\text{1}\text{2}{}^{\mathrm{?}}$ rotational band and 5 ± 3 fs (1.55 MeV) and 370 ± 25 (2.78) for the $\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{9}\text{2}{}^{\mathrm{+}}$ members of the $\text{K}{}^{\mathrm{\pi }}\text{=}\text{1}\text{2}{}^{\mathrm{+}}$ ground-state band. For the Doppler-shift attenuation analysis correction factors of the nuclear and electronic stopping powers were determined by measuring the Doppler-shift attenuation and γ-ray line shape of the 2.78 → 0.20 MeV transition and range values of 100, 200. 300 and 370 keV ¹⁹F nuclei in tantalum. All calculations were done with Monte Carlo methods. The transition strengths are discussed in terms of different theoretical predictions.     

Lifetimes of the levels 31P, 41P and 51P in Li II by the beam-foil technique

Radiative lifetimes of the Li II levels 3¹P, 4¹P and 5¹P are extracted from the observed vacuum-UV-transitions 3¹P → 2¹S, 4¹P → 2¹S, and 5¹P → 2¹S, respectively. The measured values agree well with theory.     

Electronic energy transfer from Cd(53P1 to Popop vapor

Quenching of Cd(5³P₁) by POPOP and sensitization of POPOP by Cd(5³P₁) have been investigated in the vapor phase at total pressures of 10^-1 to 10^-2 torr. Quenching of Cd is observed to occur at a rate of 5.9 X 10^-10 cm³/sec and sensitization of POPOP at a rate of 4.2 X 10^-11 cm³/sec. The sensitized fluorescence rate has been found to be consistent with Forsters long-range dipole-dipole mechanism. Selection of a donor for a possible energy transfer, vapor phase, dye laser is discussed.     

Experimental generalized oscillator strengths of the 61S0→61P1-excitation of barium

Experimental generalized oscillator strengths f(K²) for excitations of the 6¹P₁ state of Ba, measured at 200 eV and 300 eV, are compared with theoretical data obtained by Kim and Bagus. Theoretical and experimental data agree at K² < 0.3 a.u., but differ significantly at greater K².     

NCl（a^1△）／I（^2P3／2）传能体系的实验研究

利用微波放电C12／He等离子体作为Cl源，对反应NCl(a^1△) I(^2P3/2)→NCl(X^3∑) I(^2P3/2)进行了实验研究，得到了较大的I(^2P3/2)自发辐射荧光信号，检测到NCl(a^1△，b^1∑)自发辐射荧光光谱在存在少量I(^2P3/2)下发生的显著变化，其中NCl(a^1△)自发辐射荧光信号降低，同时由于I(^2P3/2)的作用，NCl(b^1∑)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(^2P3/2)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。     

Mixing between the 23S1 and 13D1Ds

Mixing between the 23S1 and 13D1Ds is studied within the 3P0 model. If mixing between these two 1 states exists, Ds1* （2700） ± and DsJ*（2860）± could be interpreted as the two orthogonal mixed states with mixing angle θ≈-80 °in the case of a special β for each meson. However, in the case of a universal β for all mesons, D_s1^*（2700） ± could be interpreted as the mixed state of 23S1 and 13D1 with mixing angle 12° < θ < 21° but D_sJ^*（2860）± seems difficult to interpret as the orthogonal partner of D_s1^*（2700）±.     

Lifetimes of high-spin yrast states in 154Er

Lifetimes for high-spin levels (between about 10 and 30 ?) in ¹⁵⁴Er have been measured by the recoil-distance method. Non-collective, moderately collective and collective E2 transitions from states with lifetimes between at most 10 and 400 ps have been found. All available data on this nucleus are discussed within the framework of the oblate coupling scheme with the addition of collective degrees of freedom.     

Lifetimes of the 2s2p53P0 states in 0 I

Beam-foil lifetimes have been measured for the partially resolved multiplet components of the 2s²2p⁴³P-2s2⁵³P⁰ transition (792 Å) in 0 I. Our lifetime results indicate that either autoionization rate is more important than reported previously or theoretical optical f-values are too small by a factor of two.     

Lifetimes of some excited states in 64Ni, 66Zn and 68Zn

Mean lives and excitation energies of the lowest levels in⁶⁴Ni,⁶⁶Zn and⁶⁸Zn were measured with the aid of the (α, α′γ) and (α, pγ) reactions. The γ-rays were detected in coincidence with the outgoing particles. The following mean lives were determined from DSA measurements: 400 ± 150 fs for the level at E_x = 1.35 MeV in ⁶⁴Ni; 270 ± 100, 210 ± 110, 330 ± 200, 80 ± 70 fs for the levels at E_x = 1.87, 2.45, 2.83, 2.94 MeV in ⁶⁶Zn, and 1300 ± 300, > 160, 600 ± 200 fs for the levels at E_x = 1.08, 1.89 and 2.76 MeV in ⁶⁸Zn, respectively.     

Pressure shifts of 1D2 Rydberg states of Mg I

Pressure shifts of the 3snd ¹D₂ Rydberg states to n = 23 have been measured for He, A and Xe and found to agree with previous results for ²P states of alkalis. Improved term values for the energy levels from n = 13 to 23 have been obtained.