微波放电解离氯分子解离效率的测量

 以Cl/Cl₂/HN₃/He为基础的NCl(a¹Δ)/I作为一种化学激光新的体系，氯原子产生的多少对该体系的研究是至关重要的。利用滴定法研究了微波解离氯分子的解离效率。用HN₃/He滴定Cl，由光学多通道分析仪监测NCl(a¹Δ)和NCl(b¹Σ)辐射的荧光。发现微波解离氯分子的效率并不是想象的那样低，在较小的氯流量下，最高的解离效率可以达到100％。     

Cl(2P)+D2→DCl+D反应中波恩-奥本海默近似有效性的交叉分子束研究

本文利用高分辨的里德堡态氘原子标识-交叉分子束装置,研究了碰撞能为4.5∽6.5 kcal/mol范围内Cl(²P)[Cl(²P_3/2)和Cl^*(²P_1/2)]与D₂的反应. 虽然自旋轨道激发态反应Cl^*(²P_1/2)+D₂在波恩-奥本海默(B-O)近似下本应是禁阻的,但实验中观测到了该反应的贡献. 通过测量靠近后向的碰撞能相关的微分散射截面连线,发现低碰撞能下的产物主要来自于B-O近似禁阻的反应Cl^*+D₂. 随着碰撞能的提高,自旋轨道基态反应Cl+D₂的反应性增加明显要比自旋轨道激发态反应Cl^*+D₂更快,并且在高碰撞能下成为产物的主要来源. 实验结果表明：在低碰撞能下,Cl^*中自旋轨道激发态的额外能量,可以帮助B-O近似禁阻的反应Cl^*+D₂越过势垒;然而当碰撞能接近和高于反应势垒时,B-O近似允许的反应Cl+D₂占主导地位. Cl/Cl^*+D₂反应中B-O近似有效性的特征与其同位素反应Cl/Cl^*+H₂是一致的.     

三氯化氮气体喷射自发分解实验研究

 在气体流动管中对三氯化氮气体喷射自发分解的现象进行了初步实验研究。在一根长80 cm，直径4 cm的圆柱形石英玻璃管中，用喷嘴向气体流动管内喷射NCl₃/He混合气体，观察到了NCl₃喷射分解时的红色火焰。测量了火焰光谱并进行了归属，认为该光谱是Cl₂(B→X)辐射跃迁。NCl­₃的喷射自发分解本质上是激波诱导发生的，即分子的动能转化为分子内能而引起的，生成的Cl原子及NCl₂自由基与NCl₃分子反应，从而得到持续燃烧火焰。实验结果表明了NCl₃自发分解反应可代替放电或燃烧作为Cl原子的来源。     

Cl+HN3产生NCl(a1Δ)和NCl(b1∑)的实验研究

 对利用微波放电直接解离Cl₂生成Cl, Cl与HN₃反应生成NCl(a^1Δ )和NCl(b^1∑)的过程进行了实验研究。得到了较强的NCl(a^1Δ 和NCl(b^1∑)自发辐射光谱,考察了Cl₂流量和He/Cl₂配比对NCl(a^1Δ 和NCl(b^1∑)生成的影响。发现对于一定的He流量,Cl₂流量对NCl(a^1Δ 和NCl(b^1∑)生成的影响存在一最佳范围,而最佳He/Cl₂配比不是一定值,而是随He流量升高而变大,在实验所考察的He流量范围（5~40 L/min）内,最佳He/Cl ₂配比在30∶1~100∶1之间。     

三氯一氟甲烷分子的正负离子对光解离动力学

在CFCl₃分子的同步辐射光激发正负离子解离过程中,利用负离子飞行时间质谱技术观测到了F^-和Cl^-(包括³⁵Cl^-和³⁷Cl^-),测量得到了³⁵Cl^-和³⁷Cl^-在7.75～22.00 eV的负离子产额效率谱. 实验得到CFCl₃→CFCl相似文献   

SBS新介质C4Cl6参数确定及性能研究

 从介质对光的吸收机理出发，研究了吸收系数较小的受激布里渊散射（SBS）新介质六氯-1,3-丁二烯（C4Cl6）。通过基本的物理参数，确定了入射光波长为1 064 nm时C₄Cl₆的SBS参数，其吸收系数约为0.003 cm^-1，声子寿命约为0.25 ns，增益系数约为4.9 cm·GW^-1。分析了入射光波长与介质SBS参数的关系，布里渊频移与入射光波长成反比，声子寿命与入射光波长的平方成正比，增益系数一般与入射光波长无关。在单池SBS系统中，利用Nd:YAG调Q激光器研究了C₄Cl₆的SBS性能。实验结果表明：由于其吸收系数小，与具有相同增益系数的H₂O比较，C₄Cl₆具有较高的能量反射率（饱和能量反射率大于55%）和较宽的SBS脉宽；由于其声子寿命短，与具有相同吸收系数的CS₂比较，C₄Cl₆的SBS波形上升时间较短。吸收系数小和声子寿命短的特点，使C₄Cl₆适合作为放大池介质，这对优化SBS介质选取，提高SBS系统性能具有一定意义。     

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。     

使用时间切片离子速度成像技术研究CF2Cl2光解动力学

本文使用时间切片离子速度成像技术结合共振增强多光子电离技术研究了CF₂Cl₂分子在235 nm附近的光解动力学. 通过测量CF₂Cl₂分子在235 nm附近单光子解离产生的氯原子影像,直接得到了解离产物的速度分布和角分布. 激发态氯原子的速度分布包含高动能组分和低动能组分,分别对应³Q₀电子态的直接解离和由于内转换引起的基态预解离. 基态氯原子的速度分布也包含高动能组分和低动能组分,分别对应³Q₀与¹Q₁电子态的预解离和由于内转换引起的基态预解离. 自由基解离通道被确认,二次解离通道和三体解离通道被排除.     

氧碘化学激光器中转盘式单重态氧发生器研究

 通过对单重态氧发生器（SOG）内的传质、传热及化学动力学过程的研究，提出高效SOG的设计原则，并研制出一台可用于高功率超音速氧碘化学激光器（COIL）的SOG， 其Cl₂流量在0.6~1mol/s时，O₂(¹Δ)分压可达333.3~519.9Pa； O₂(¹Δ)浓度达到50%~68%；Cl₂利用率大于90%；混合气中水蒸汽含量小于10%。     

在193 nm关于Si2分子的离子解离动力学的成像研究

在193 nm的单色激光实验中,本文利用时间切片离子速度成像技术,研究了经193 nm双光子电离得到的Si₂⁺的解离反应动力学过程. 根据实验得到的Si⁺离子的速度成像,观测到了两种离子直接解离通道：Si(³P_g)+Si⁺(²P_u)和Si(¹D₂)+Si⁺(²P_u). 电子基态的Si₂分子处于v=0∽5的振动态上,其经过双光子电离后激发到Si₂⁺离子的多个电子激发态势能面,生成主要通道Si(³P_g)+Si⁺(²P_u),其中v=1的解离信号最强. 此外,由于势能曲线2²Π_g与3²Π_g相同对称性引起的避免性势能面交叉,生成次要反应通道Si(¹D₂)+Si⁺(²P_u). 通道Si(¹D₂)+Si⁺(²P_u)的产物亦可以由生成的基态Si₂⁺(X⁴Σ_g^-)吸收一个193 nm光子后解离得到,其对应产物则具有更大的动能.     

微波解离氯分子及其解离率的研究

通过微波解离Cl     

High-pressure-activated carbon tetrachloride decomposition

The pressure-induced molecular dissociation as one of the fundamental problems in physical sciences has aroused many theoretical and experimental studies. Here, using a newly developed particle swarm optimization algorithm, we investigate the high-pressure-induced molecular dissociation. The results show that the carbon tetrachloride （CC14） is unstable and dissociates into C2C16 and C12 under approximately 120 GPa and more. The dissociation is confirmed by the lattice dynamic calculations and electronic structure of the Pa3 structure with pressure evolution. The dissociation pressure is far larger than that in the case of high temperature, indicating that the temperature effectively reduces the activation barrier of the dissociation reaction of CC14. This research improves the understanding of the dissociation reactions of CC14 and other halogen compounds under high pressures.     

Resonance enhanced multiphoton ionisation (REMPI) detection of Cl(2Pj) atom in the photodissociation of halogenated pyrimidines at 235 nm: role of triplet states

ABSTRACT

The dynamics of chlorine atom (²P_j) formation in the photodissociation process of halogen substituted pyrimidines, namely, 2,4,6-trichloropyrimidine and 5-chloro-2,4,6-trifluoropyrimidine have been studied around 235?nm using Resonance Enhanced Multiphoton Ionisation Time-of-Flight Mass Spectrometry technique. For the chlorine atom dissociation channel, we have determined the translational energy distribution, the recoil anisotropy parameter, β, and the spin–orbit branching ratio. In both the molecules, the TOF profiles for Cl (²P_3/2) and Cl* (²P_1/2) are found to be independent of laser polarisation suggesting a zero value for β, within the experimental uncertainties. For 2,4,6-trichloropyrimidine, the average translational energies for Cl and Cl* elimination channels are determined to be 6.0?±?1.2 and 7.0?±?1.5 kcal/mol, respectively. Similarly, for 5-chloro-2,4,6-trifluoropyrimidine, the average translational energies for Cl and Cl* elimination channels are determined to be 6.5?±?1.2 and 7.9?±?1.6 kcal/mol, respectively. Computational calculations are performed to generate the potential energy curves along the dissociating C-Cl bond using equation of motion coupled cluster with single and double excitations (EOM-CCSD) method. Computational studies suggest the role of triplet states in the photodissociation process forming the Cl atom.     

磁控溅射Cl掺杂CdTe薄膜的孪晶结构与电学性质

CdTe用作薄膜太阳能电池吸收层需要经过氯处理才能得到高的光电转换效率,其中Cl原子的作用机理仍然没有完全被理解.实验发现Cl原子主要偏聚在CdTe晶界处,对晶界有钝化作用,而有第一性原理计算认为Cl原子掺入CdTe晶格能够引入浅能级提高光电转换效率.为了验证Cl原子掺杂是否对CdTe的光电转换效率有益,本文通过磁控溅射制备了100 ppm(ppm=1/1000000)Cl原子掺杂的CdTe(CdTe:Cl)薄膜并研究了薄膜的晶体结构与电学性质,同时对比了正常氯处理的无掺杂CdTe薄膜与CdTe:Cl薄膜之间的性质区别.实验发现Cl原子掺杂会在CdTe:Cl中形成大量仅由几个原子层构成的孪晶,电子和空穴在CdTe:Cl薄膜中没有分离的传导通道,而在氯处理后的CdTe薄膜中电子沿晶界传导,空穴沿晶粒内部传导.磁控溅射沉积的CdTe:Cl多晶薄膜属于高阻材料,退火前载流子迁移率很低,退火后载流子浓度降低到本征数量级,电阻率提高.CdTe:Cl薄膜电池效率远低于正常氯处理的无掺杂CdTe薄膜电池效率.磁控溅射制备的非平衡重掺杂CdTe:Cl多晶薄膜不适合用作薄膜太阳能电池的吸收层.     

Infrared multiphoton dissociation of 1,2-dichloroethyltrifluorosilane

Infrared multiphoton absorption and dissociation of 1,2-dichloroethyltrifluorosilane molecules under the action of pulsed TEA CO₂ laser were experimentally studied. The composition of dissociation products was analyzed. The only products of dissociation have been found to be stable molecules: chloroethylene and trifluorochlorosilane. Dissociation proceeds via chlorine atom transfer from carbon to silicon. The silicon isotope-selective infrared multiphoton dissociation was performed at different wavelengths of the CO₂-laser radiation. High degrees of silicon isotope separation have been achieved.     

低气压下XeCl准分子的形成研究

本工作利用高频介质阻挡放电对较低气压(70～1330 Pa)Xe/Cl_2混合气体中XeCl准分子的形成过程进行研究。通过探测不同Xe/Cl_2混合气压和不同Xe/Cl_2混合比条件下放电等离子体在285～315nm波长范围的荧光发射谱,得到了XeCl准分子在308nm附近的荧光发射以及荧光强度随气压变化曲线。得出该实验条件下生成XeCl准分子的最佳Xe/Cl_2混合比为4:1。     

The Kinetic Mechanisms of the Trapping of Atmospheric Gases by Marine Salt Surfaces: IX. The Heat of Adsorption of Cl Atoms on the Surface of NaCl

The heterogeneous trapping of chlorine atoms on the surface of NaCl was studied using two coaxial stream reactors connected to an EPR cavity or a mass spectrometer. The kinetics of trapping was measured by the EPR method over a wide range of chlorine atom concentrations (10¹⁰–10¹³ cm^?3) at temperatures of 250–330 K. At [Cl] ≥ 10¹² cm^?3, chlorine atoms were recorded by the EPR method in the gas phase. At lower concentrations (~10¹⁰?3 × 10¹¹ cm^?3), Cl atoms were replaced with RO₂ radicals by adding hexane RH and O₂ at the entrance of the EPR cavity. This was followed by the matrix isolation of RO² in the cavity at liquid nitrogen temperature. The probability of the trapping of chlorine atoms on the chemically inactive surface of NaCl was found to increase as the concentration of Cl grew. The temperature dependence of the trapping coefficient γ was pronounced at a concentration of chlorine atoms of ~3 × 10¹⁰ cm^?3, whereas no such dependence was observed at a chlorine concentration of ~ 10¹³ cm^?3. The recombination of Cl atoms was well described by the Rideal-Eley mechanism, and the heat of adsorption of chlorine atoms on the inactive surface of NaCl was estimated at Q = 17 ± 0.6 kcal/mol. It was shown mass spectrometrically that the trapping coefficient γ of Cl atoms decreased with the time of measurements, like the partial coefficient of the formation of the HCl product, whereas the partial coefficient of the formation of the Cl₂ product, conversely, increased with the time. The characteristic time of the attainment of stationary values by all the γ coefficients weakly depended on the initial concentration of Cl and equaled several dozen seconds. Reactions of adsorbed Cl atoms formed in the trapping of NO₃ radicals by the surface of marine salt NaCl in coastal troposphere are discussed.     

Influence of external electric field on the transfer of protons in hydrogen-bonded systems

The LCAO MO self-consistent field method in combination with the 6-31** basis set is used to calculate sections of the potential energy surface for a proton in the NH₃…HCl system in the presence of an external electrostatic field. The field strength is varied in the range of 0.000 to 0.017 a. u. In the absence of the field, the potential of the proton in the isolated complex has one well, the N–Cl distance is equal to 2.92 Å, and the NH₃…H–Cl bond is a hydrogen bond. With increasing distance between the N and Cl atoms, a second well appears in the potential, with the well near the Cl atom remaining deeper. In the presence of an external electric field, with increasing its strength, the depth of the well near the N atom increases, while the height of the barrier for proton transfer from the chlorine to the nitrogen atom decreases. At a certain field strength, the well near the nitrogen atom becomes deeper than that near the chlorine atom, so the proton moves to the nitrogen, making the complex ionic. Thus, the external electric field can influence the type of chemical bond in NH₃…HCl system.     

A Model for the Bulk Plasma in an RF Chlorne Discharge

A model has been constructed to describe the electrical characteristics of the central bulk plasma region in a 13.56-MHz parallel-plate discharge in chlorine at pressures of about 1 torr. This region is modeled as a volume-controlled plasma with the electron balance dominated by single-step electron-impact ionization and attachment and with the electron energy distribution function in equilibrium with the local instantaneous electric field. Relationships between the ionization frequency, the attachment frequency, the electron drift velocity, and the electric field are provided by solutions of the Boltzmann equation for mixtures of Cl2 and Cl which result from Cl2 dissociation. From a measured current waveform and Cl2/Cl density ratio, the model generates the local electric-field waveform, the time-varying electron density, and the power density in the central portion of the bulk plasma. The calculated time-averaged power input per unit discharge length compares well with experimentally determined values.