低能Ar3+ + Ar碰撞反应过程实验研究

测量了入射离子能量为27 keV、45 keV和66 keV时Ar3 Ar碰撞反应各子过程的分截面,通过将其归一化到Bliman,Dousson等人所测量的截面值,获得了绝对截面.结果表明,该能区电子俘获过程仍占主导地位,但转移电离过程已不能忽略.结果还表明,各子过程反应截面基本不随能量变化.与考虑自电离的MCBM(Molecular Coulombic overBarrier Model)模型比较发现,模型所给截面普遍高于实验测量值,这在一定程度上是由于归一化时带来的系统误差.在误差允许的范围内,单电子和双电子俘获截面符合的比较好,但三电子俘获截面却相差一个数量级.对于实验观测到的转移电离过程,模型却预言并没有此过程发生.     

Rotational analysis of the c3Πu–b3Πg system of P2

The rotationally resolved spectra of the c³Π_u–b³Π_g system of P₂ in the 16620–17860 cm^?1 region is reanalyzed here to obtain more assignments of the rotational lines and more accurate molecular constants. Approximately 500 spectral lines were assigned to six subbands: the Ω=0, 1 and 2 components of the (2, 3) band, the Ω=0 and 2 components of the (1, 3) band and the Ω=2 component of the (1, 2) band. Because of perturbations in the c³Π_u (υ=2) state, the Λ-doubling in the ³Π₂–³Π₂ subband of the (2, 3) band was resolved. By the weighted nonlinear least-squares fitting using two types of effective Hamiltonians, more accurate molecular constants for the υ′=1 and 2 levels in the c³Π_u state and for the υ″=2 and 3 levels in the b³Π_g state of P₂ were derived.     

N2+分子离子的B2Σu+、A2Πu和X2Σg+电子态光谱研究

采用光外差 磁旋转 速度调制吸收光谱技术 ,在可见光波段范围 16 80 0～ 175 73cm-1,对N2 + 的A2 Πu-X2 Σ+ g(12 ,6 )、(11,5 )、(7,2 )带和B2 Σ+ u -X2 Σ+ g(1,5 )带进行了测量和分析 ,推导了双原子分子振转能级在受到微扰作用时的有效哈密顿量形式 ,并分析了N2 + 的A2 Πu-B2 Σ+ u 之间存在的微扰相互作用 ,通过与实验数据的拟合得到了精确的电子态微扰常数 ξe、ηe.     

2H_2+O_2+3Ar预混气螺旋爆轰内部结构的实验探索

为研究分析内部胞格结构特点及壁面三波点轨迹向内部延伸模式,通过设计的爆轰实验管道(内径63.5 mm)来记录2H_2+O_2+3Ar的爆轰径向波和周向波。首先,给出侧壁烟膜及对应端面烟熏玻璃记录.由单头螺旋结果可知螺旋结构一般不是固定的,远离壁面处结构发生改变,径向波和周向波之间的相互作用可能导致不同的内部结构。然后,测量了横波与管轴的夹角,随螺旋头数增大而减小,最终趋向于一个较小值(31°),与声学模式计算夹角一致,以明确爆轰波符合物理波的传播特性。并给出了壁面轨迹向内部延伸的描绘。初始压力足够大时(13.82 kPa),爆轰内部结构趋于规律,在端面形成了规则的近圆形胞格结构。最后计算了端面胞格尺寸,其发展规律与壁面横波间距尺寸一致。     

Molecule opacities of X~2Σ~+, A~2Π, and B~2Σ~+ states of CS~+

Carbon sulfide cation(CS~+) plays a dominant role in some astrophysical atmosphere environments. In this work, the rovibrational transition lines are computed for the lowest three electronic states, in which the internally contracted multireference configuration interaction approach(MRCI) with Davison size-extensivity correction(+Q) is employed to calculate the potential curves and dipole moments, and then the vibrational energies and spectroscopic constants are extracted. The Frank–Condon factors are calculated for the bands of X~2~+Σ~+–A~2Π and X~2Σ~+–B~2Σ~+systems, and the band of X~2Σ~+–A~2Π is in good agreement with the available experimental results. Transition dipole moments and the radiative lifetimes of the low-lying three states are evaluated. The opacities of the CS~+ molecule are computed at different temperatures under the pressure of 100 atms. It is found that as temperature increases, the band systems associated with different transitions for the three states become dim because of the increased population on the vibrational states and excited electronic states at high temperature.     

C2（a 3Πu）+NO 的反应机理研究

在G2 (CC ,MP2 )理论水平上研究了C2 (a3 Πu)自由基与NO分子的反应 .计算了反应体系最低二重态势能面上各驻点的构型参数、振动频率和能量 ,揭示了此反应存在两种反应机理 :由NO中的O原子进攻C2 自由基形成CCON中间体的CCON机理和NO中的N进攻C2 自由基形成CCNO中间体的CCNO机理 ,分析了对应与这两种反应机理的五个可能的反应通道 ,得出了由NO中的N原子进攻3 C2 自由基 ,生成中间体CCNO自由基 ,最终得到产物CN +CO的通道是最有利的通道 .     

A theoretical study of the non-adiabatic charge transfer process Ar2+ (3 P) + He(1 S) → Ar+(2 P) + He+(2 S)

CI calculation with a large basis have been used to calculate the two lowest ³Π adiabatic potential energy curves for the title reaction. These potentials have been transformed to diabatic potentials by employing a recipe based on the CI coefficients. Quantum mechanical close coupling calculations in the diabatic basis have produced total and differential cross sections which are in good agreement with experimental data. Full quantum mechanical and Landau-Zener calculations of the total cross section are in fair agreement with recent experimental measures and by small changes to the diabatic potentials can be brought into essentially exact agreement.     

Enhancement of the electrical properties of carbon nanotubes with Ar–N2 plasma treatment

Optical emission spectroscopy and Langmuir probe are used to investigate the low pressure inductively coupled Ar–N₂ plasmas as function of rf power, filling pressure and Ar content in N₂ discharge. It is observed that the active species generation, dissociation fraction and electron temperature significantly depends on discharge parameters and may be used to optimize the plasma reactor. Mixture of SWCNTs and MWCNTs are treated for different treatment time (0–120 min) at optimum discharge conditions. Changes induced in the elemental composition, surface morphology, crystallographic structure, and structural disorder in the plasma irradiated CNTs are analyzed by EDX, FTIR, SEM, XRD and Raman spectroscopy, respectively. Ar–N₂ mixture plasma treatment of CNTs lead to a significant increase in the electrical conductivity, modify the microstructure and induce structural disorder and cause a transition of crystalline phase from well crystalline to an amorphous structure.     

Study on the A~2Π_(3/2u), B~2Δ_(3/2u), and X~2Π_(3/2g) states of Cl_2~+ including its isotopologues

Adopting the experimentally available vibrational constants in a recent analysis of the strong perturbation between the A22Π3/2u and BΔ3/2u states of Cl+2in the A–X band system [Gharaibeh et al. 2012 J. Chem. Phys. 137 194317], an unambiguous vibrational assignment of the bands reported previously is carried out. The equilibrium rotational constants Be and α e of the X2Π3/2g and A2Π3/2u states for35Cl+2and35Cl37Cl+and those of the B2Δ3/2u state for35Cl+2are obtained by fitting the experimental values of Bυ. In addition, the values of Be and α e of these three states for the minor isotopologues35Cl37Cl+and37Cl+2are predicted by employing the isotopic effect. The values of equilibrium internuclear distance Re of the three states for the three isotopologues are calculated as well.     

icMRCI+Q理论研究Cl_2~+离子 X~2Π_g和A~2Π_u态的光谱性质

利用考虑Davidson修正的内收缩多参考组态相互作用(icMRCI+Q)方法结合相关一致基组aug-cc-pV6Z计算了Cl_2~+离子X~2Π_g和A~2Π_u态及其它们所产生的4个Ω态的势能曲线.为了提高势能曲线的可靠性和精确性,计算中考虑了旋轨耦合效应、核价相关和标量相对论修正.基于得到的势能曲线,获得了X~2Π_g、A~2Π_u态和4个Ω态的光谱常数和振动能级,与已有的实验结果非常符合.分析表明首次报道的A~2Π_(u,1/2)态的光谱常数以及X~2Π_g, A~2Π_u, A~2Π_(u,3/2)和A~2Π_(u,1/2)态的振动能级也应是可靠的.     

Theoretical study on structures of Ga3N, GaN3, Ga3N2 and Ga2N3 clusters

The structures of Ga_3N, GaN_3, Ga_3N_2 and Ga_2N_3 clusters are studied using the full-potential linear-muffin-tin-orbital molecular dynamics (FP-LMTO MD) method. Four structures for Ga_3 N, five structures for GaN_3, nine structures for Ga_3N_2 and nine structures for Ga_2N_3 have been obtained. The most stable structures of these clusters are planar ones. A strong dominance of the N－-N bond over the Ga－-N and Ga－-Ga bonds appears to control the structural skeletons, supporting the previous result obtained by Kandalam and co-workers. The most stable structures of these small GaN clusters displayed semiconductor-like properties through the calculation of the HOMO－LUMO gaps.     

Chemical Synthesis of C3N and BC2N Compounds

A chemical reaction for the preparation of B-C-N compounds by using carbon tetrachloride （CC14）, boron tribromide （BBr3）, lithium nitride （Li3N） and sodium as reactants has been carried out at the temperature of 400℃. Measurements of FTIR, XRD, TEM and EELS show that two kinds of compounds have been formed in the prepared sample. One is hollow sphere-like C-N with an amorphous, structure; the other is piece-like polycrystalline B-C-N with the hexagonal structure. Their determined compositions are close to C3N and BC2N, respectively.     

用微扰增强双共振对Na2 2 3Πg和3 3Πg能级进行新观测

Na22^3Пg和3^3Пg态在34860cm^-1(相对基态Te)和3s+3d解离限之间的Ω=0，1，2能级进行了脉冲激光微扰增强双共振探测、观测到两个态之间强烈的相互微扰．给出忽略微扰情况下Ω=0能级的Tv和Bv。     

Paul阱中囚禁的低能Ar2+离子与Ar的电荷转移

在Paul阱中产生并选择囚禁了单一的Ar2 离子,得到低能Ar2 与Ar的电荷转移速率系数为5.84(0.677)×10-10cm3·s-1及其零氩气压强下的离子衰减速率为0.46 s-1,为下一步进行多电荷离子的亚稳态寿命研究提供了有价值的实验参考数据.     

State selective predissociation spectroscopy of hydrogen chloride ions (HCl+) via the A2Σ+ ← X2Π3/2 transition

The photodissociation of hydrogen chloride ions (HCl⁺) has been investigated through the A²Σ⁺ (ν′ = 6, 7 and 8) ← X ²Π_3/2 (ν″ = 0) transition. The spectra reveal that state selective photodissociation with complete resolution of the spin, orbital, and rotational angular momentum is possible in the A ²Σ⁺ (ν′ = 6) state. The analysis of these spectra yields the rotational and the spin-rotation coupling constant of the A ²Σ⁺ (ν′ = 6) state. The lifetime of HCl⁺ decreases significantly with increasing vibrational excitation in the ²Σ⁺ state. Within the experimental error limits no J dependence of the lifetime is observerd. The state selective photodissociation of the HCl⁺ ions is also shown to be a very sensitive probe for unexpected parity transitions in the 2 + 1 REMPI formation of the HCl⁺ ions in the X 2Π_3/2 (ν″ = 0) state.     

Thermal Decomposition Behaviour of ZB3N2 Powder

Thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) are employed to investigate the thermal decomposition behaviour of zinc nitride powder, which indicated that the thermal oxidation of zinc nitride powder in air follows the two-step reaction model. When the temperature is between 200 and 500℃,compact ZnO or ZnxOyNx layers in the surface of zinc nitride powder will begin to form, and prevent the interior of zinc nitride powder from the thermal oxidation. When the temperature is higher than 500℃, fast thermal oxidation occurs in the interior of zinc nitride powder. Over 750℃, all the zinc nitride will turn into zinc oxide.The x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) of the zinc nitride powder annealed at different temperature in air are consistent with the two-step reaction model.     

Spectroscopic study of B2Σ+–X1 2Π1/2 transition of electron electric dipole moment candidate PbF

PbF, a valuable candidate for measuring the electron electric dipole moment (eEDM), is of great significance in measuring its spectrum and deriving its molecular constants in experiment. In the present work, the rovibronic spectrum of the B$^{2}{\Sigma }^{+}$-X$_{1}^{\, 2}{\Pi }_{1/2}$ transition of PbF in a wavelength range of 260 nm-285 nm is studied by the laser ablation/laser induced fluorescence method. The molecular parameters of the X$_{1}^{\, 2}{\Pi }_{1/2}$ (${v'}=0)$ and B$^{2}{\Sigma }^{+}$ (${v}'=0, 1$) states are derived from the recorded spectra of the (0, 0) and (1, 0) bands of the B$^{2}{\Sigma }^{+}$-X$_{1}^{\, 2}{\Pi }_{1/2}$ transition. Also, the Franck-Condon factors (FCFs) of the transitions between the B$^{2}{\Sigma }^{+}$ and X$_{1}^{\, 2}{\Pi }_{1/2}$ states are calculated by the RKR/LEVEL method and the Morse potential method, respectively.