Rb（5PJ）＋Rb（5PJ）→Rb（5JS）＋Rb（nl=5D，7S）碰撞能量合并

研究了Rb(5PJ)+Rb(5PJ)→Rb(nlJ')+Rb(5S)碰撞能量合并过程,利用单模半导体激光器分别共振激发Rb原子的5P1/2或5P3/2态,利用另一与泵浦激光束反向平行的单模激光束作为吸收线探测激发态原子密度及其空间分布,吸收线分别调至5P1/2→5D3/2和5P3/2→7S1/2跃迁.由激发态原子密度和谱线荧光比得到碰撞能量合并过程的截面,对5P3/2激发,碰撞转移得到5D5/2,5D3/2和7S1/2的截面分别是(1.32士0.59)×10-14,(1.18士0.53)×10-14和(3.21士1.44)×10-15cm2;对5P1/2激发,碰撞转移到5D5/2和5D3/2的截面分别是(6.57士2.96)×10-15和(5.90士2.66)×10-15cm2.与其他的实验结果进行了比较.     

Resonant Reaction in Rb-Cs Vapour Mixture Rb（5P1/2） ＋ Cs（6P3/2） → Cs（8S1/2）＋Rb（5S1/2）

We experimentally study energy-pooling collision in the Rb-Cs vapour mixture at low densities in a cell. Atoms are excited to Rb（5P1/2） and Cs（6P3/2） states using two single-mode diode lasers. To isolate the heteronuclear contribution in the fluorescence spectrum, a double-modulation technique is adopted. The excited-atom density and spatial distribution are mapped by monitoring the absorption of a counterpropagating single-mode diode laser beam, tuned to Rb（5P1/2 → 7S1/2） and Cs（6Pa/2 → 8S1/2） transitions, respectively, which could be translated parallel to the pump beams. The excited atom densities are combined with the measured fluorescence ratios to determine cross section for the energy-pooling process [i.e. Rb（5P1/2） ＋Cs （6P3/2） → Cs（8S1/2）＋Rb （5S1/2）]. The cross section is 3.79 × 10^-14 cm^2 ± 45%.     

Na（3P）＋Rb（5P）碰撞能量转移截面

置于同一池中的钠原子和铷原子，分别被连续染料激光器和铷光谱灯激发到Ｎａ（３Ｐ），Ｒｂ（５Ｐ），Ｎａ（３Ｐ）原子密度由吸收等效宽度技术测定，利用调制技术分离出了凡异核碰撞产生的荧光光谱，观察到了Ｎａ（３Ｐ）和Ｒｂ（５Ｐ）间的碰撞能量俣并现象，并测定了其碰撞截面。     

与铷（5^2S1／2）原子碰撞产生的铷7^2D态精细结构转移截面

本文报道使用蒸汽泡和两光子两步激发方法,测量原子激发态敏化荧光I_(3/2)~1和直接荧光I_(3/2)~2其与温度的关系,得到与基态(5~2S_(1/2)铷原子碰撞产生的铷7~2D_(5/2)→7~2D_(3/2)和7~2D_(3/2)→7~2D_(5/2)精细结构转移截面分别为:σ_(fs)=4.7×10~(-13)cm~2、σ_(fs)~’=7.0×10~(-13)cm~2;碰撞转移出7~2D双态的转移截面σ_(tr)(5/2)=0.62×10~(-13)cm~2.由计算的7~2D态几何截面σ_(geom)能够相对很好地描述σ_(fs)和σ_(fs)~’的数量级.     

Na（4D）＋Na（3S）=Na（4F）＋Na（3S）碰撞能量转移截面

利用双光子吸收，将Ｎａ（３Ｓ）原子激发到４Ｄ态，测量了Ｎａ（４Ｄ）＋Ｎａ（３Ｓ）＝Ｎａ（４Ｆ）＋Ｎａ（３Ｓ）碰撞能量转移截面，因为直接由４Ｆ→３Ｄ的荧光不能探测，所以检测３Ｄ→３Ｐ级联荧光讯号。结合基态钠原子密度的测量，给出了截面值σ４Ｄ→４Ｆ－１．３×１０＾－１４±２８％（ｃｍ＾２）。     

Rb(5PJ)+Rb(5PJ)→Rb(5S)+Rb(nl=5D,7S)碰撞能量合并

研究了Rb(5PJ) Rb(5PJ)→Rb(nlJ') Rb(5S)碰撞能量合并过程,利用单模半导体激光器分别共振激发Rb原子的5P1/2或5P3/2态,利用另一与泵浦激光束反向平行的单模激光束作为吸收线探测激发态原子密度及其空间分布,吸收线分别调至5P1/2→5D3/2和5P3/2→7S1/2跃迁.由激发态原子密度和谱线荧光比得到碰撞能量合并过程的截面,对5P3/2激发,碰撞转移得到5D5/2,5D3/2和7S1/2的截面分别是(1.32士0.59)×10-14,(1.18士0.53)×10-14和(3.21士1.44)×10-15cm2;对5P1/2激发,碰撞转移到5D5/2和5D3/2的截面分别是(6.57士2.96)×10-15和(5.90士2.66)×10-15cm2.与其他的实验结果进行了比较.     

Influence of rotational excitation and collision energy on the stereo dynamics of the reaction： N（4S）＋H2 （v = 0, j = 0, 2, 5, 10） →NH（X3∑-）＋H

The N+H₂ reaction has attracted a great deal of attention from both the experimental and the theoretical community, and most of the attention has been paid to the first excited state N(²D) atoms in collisions with hydrogen molecules and the scalar properties of the reaction. In this paper, we study the stereo dynamical properties and calculate the reaction cross sections of the N(⁴S) + H₂ (v=0, j=0, 2, 5, 10) → NH(X³Σ^-) + H using the quasi-classical trajectory (QCT) method on an accurate NH₂ potential energy surface (PES) reported by Poveda and Varandas [Poveda L A and Varandas A J C 2005 Phys. Chem. Chem. Phys. 7 2867], in a collision energy range of 25 kcal·mol^-1-140 kcal·mol^-1. Results indicate that the reactant rotational excitation and initial collision energy both have a considerable influence on the distributions of the k-j′ correlation, the k-k′-j′ correlation and k-k′ correlation. The differential cross section is found to be sensitive to collision energy.     

Stereodynamics of the O（^3p） with H： （D2） （v = O,j =O） reaction

Quasi-classical trajectory theory is used to study the reaction of O（3p） with H2 （D2） based on the ground 3A″ potential energy surface （PES）. The reaction cross section of the reaction O＋H2→＋OH＋H is in excellent agreement with the previous result. Vector correlations, product rotational alignment parameters （P2（j′. k）） and several polarizeddependent differential cross sections are further calculated for the reaction. The product polarization distribution exhibits different characteristics that can be ascribed to different motion paths on the PES, arising from various collision energies or mass factors.     

Quasi-classical trajectory study of the isotope effect on the stereodynamics in the reaction H（2S） ＋ CH（X2∏; v=o,j= 1）→ C（1D）＋H2（X1∑g＋）

The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory （QCT） method on the 11At potential energy surface at a collision energy of 23.06 kcal/mol. The angular distributions P（φr ）, P（θr）, P（θr, φr）, and the polarization-dependent generalized differential cross sections are calculated, which demonstrate the observable influences on the rotational polarization of the product by the isotopic substitution of H with D.     

Theoretical prediction of the optimal conditions for observing the stereodynamical vector properties of the C（3P）＋OH （X2∏）→CO（X1S＋）＋H（2S） reaction

The best optimal initial reactant state and collision energy for observing the stereodynamical vector properties of the title reaction in the ground electronic state X2A’ potential energy surface （PES）[Zanchet et al. 2006 J. Phys. Chem. A 110 12017] are theoretically predicted using the quasi-classical trajectory （QCT） method for the first time. The calculated results reveal that the smallest value of the rotational quantum number j, larger vibrational quantum number v, and the lower strength of collision energy should be selected for offering the most obvious picture about the stereodynamical vector properties. Polarization-dependent differential cross sections and the angular momentum alignment distribution, P（θr） and P（Φr） in the center-of-mass frame, are obtained to gain an insight into the alignment and orientation of the product molecules. The rotational angular momentum vector j’ of CO is aligned to be perpendicular to reagent relative velocity k. The product polarizations align along the y axis, pointing to the positive direction of the y axis. A new method is developed to investigate massive reactions with various initial states and to further study the vector properties of the fundamental reactions in detail.     

Theoretical study of stereodynamics for the O（3P） ＋ H2 → OH ＋ H reaction

This paper employs the quasi-classical trajectory calculations to study the influence of collision energy on the title reaction on the potential energy surface of the ground ³A' triplet state developed by Rogers et al. (J. Phys. Chem. A 2000 104 2308). It calculates the product angular distribution of P(θ_r), P(φ_r) and P(θ_r, φ_r) which reflects vector correlation. The distribution P(θ_r) shows that product rotational angular momentum vectors j' of the products are strongly aligned along the relative velocity direction k. The distribution of P(φ_r) implies a preference for left-handed product rotation in planes parallel to the scattering plane. Four different polarisation-dependent cross-sections are also presented in the centre-of-mass frame. Results indicate that OH is sensitively affected by collision energies of H₂.     

Transfer Ionization of Helium in Collisions with C^q＋ and O^q＋ （q =1 - 3）

Cross-section ratios σTI/σSC of transfer ionization （TI） to single capture （SC） of C^q＋- and O^q＋-He （q = 1 - 3） collisions in the energy range of 15-440 keV/u （0.8-4.2 vBohr） are experimentally determined. It is shown that σTI/σSC strongly depends on the projectile velocity, and there is a maximum for E（keV/u）/q1/2 ≈, 150. Combining the Bohr-Lindhard model and the statistical model, a theoretical estimate is presented, in reasonable agreement with the experimental data when E（keV//u）/q^1/2 〉 35.     

Single electron capture in collisions of N^q＋ （q = 5, 6, 7） ions with helium

Close-coupling calculations are carried out for cross sections of the single electron capture in collisions of N^q+ (q = 5, 6, 7) ions with helium atoms in the collision velocity range from 0.3 a.u. to 1.8 a.u. The relative importances of the single ionization (SI) to the single capture (SC) are investigated for the N^q+ (q = 5, 6, 7) projectiles, respectively. The SI/SC cross section ratio for the N⁷⁺ projectile obtained from our calculations is in excellent agreement with the experimental data. The ratio curves also show us distinct behaviours when the charge of the projectile is different. The partial electron capture cross sections for different projectiles indicate that the electron on the target He atom tends to be captured by the projectile into its lower orbital of the outer shell with the decreasing projectile charge.     

Quasi-classical trajectory investigation on the stereodynamics of Li ＋ DF（v=1-6,j=0）→LiF＋D reaction

In this paper, the stereodynamics of Li ＋ DF → Li F ＋ D reaction is investigated by the quasi-classical trajectory（QCT）method on the ^2A＇ potential energy surface（PES） at a relatively low collision energy of 8.76 kcal/mol. The scalar properties of the title reaction such as reaction probability and cross section are studied with vibrational quantum number of v = 1–6. The product angular distributions P（θr） and P（φr） are presented in the same vibrational level range. Moreover, two polarization-dependent generalized differential cross sections（PDDCSs）, i.e., the PDDCS00 and PDDCS22＋are calculated as well. These stereodynamical results demonstrate sensitive behaviors to the vibrational quantum numbers.     

Luminescence Kinetic Model for Long-Afterglow Phosphor （Sr0.5 Ca1.5 ） MgSi2O7 ：Eu^2＋ ,Dy^3＋

A luminescence kinetic model for the green-emission long-afterglow phosphor (Sr0.5 Ca1.5)MgSi2O7:Eu^2 ,Dy^3 is proposed based on the studies of the thermoluminescence and isothermal decay curves at different temperatures.The isothermal decay curves at different temperatures meet the hyperbolic law and show to be dependent on temperature. Combined with the decay curves and the thermoluminescence curves, it can be concluded that the long afterglow of this material originates from the traps with energy distribution rather than a single level trap.Upon illumination with ultra-violet or visible light, the trap filling can proceed via excitation of 4f electrons to the 5d level of Eu^2 ions. After excitation, 5d electrons can be transferred to the trap related to Dy3 ions, and Eu^3 is left behind. Upon subsequent heating, the electron is released from this trap and recombines with Eu^3 to produce Eu^2 emission.     

e-Ar(3p54s,J=2)的微分散射截面

电子与氩原子激发态的碰撞是个很重要的过程，对研究发射的光谱、激光物理和等离子体过程都很有意义.分析3p⁵4s的3p⁵4p J=3能级截面提供了很有价值的原子物理过程，也为在强激光场作用下氩原子发射高次谐波的单原子行为提供依据. 关键词：