电离

Atom, molecule or radical can be excited to a specific intermediate state by absorbing m laser photons, then the parent ion can be produced by absorption of another n laser photons. The ion yield can be increased drastically due to resonant absorption, comparing with the ion yield in non-resonant absorption. This multiphoton process is usully called Resonance Enhanced Multiphoton Ionization. REMPI technique plays an important role in detecting the high electronic excited states of atoms, molecules and radicals.

原子、分子、离子或自由基在同时吸收m个光子从下态共振跃迁到中间态后再吸收n个光子使其电离的过程中，下态和中间态的多光子共振吸收使得产生的离子信号强度比相应的非共振多光子电离得到的离子信号强度有很大的增强，该过程称为共振增强多光子电离REMPI。

This dissertation is concerned with the kinetics of the nonequilibrium dissociation and ionization of gases that are significant in the high temperature gas dynamics. There are two parts in the dissertation. In the first part, the kinetics of dissociating gas, a theoretical calculation is made of the nonequilibrium dissociation of the diatomic molecule behind a strong shock wave front.

中文题名高温气体解离和电离动力学研究副题名外文题名 The study of the kinetics of dissociation and ionization in the high temperature gases 论文作者王苏导师崔季平何宇中研究员范秉诚高级工程师学科专业一般力学研究领域\研究方向学位级别博士学位授予单位中国科学院力学研究所学位授予日期2001 论文页码总数125页关键词气体动力学电离复合非平衡解离速率振动－解离耦合馆藏号BSLW /2003 /O354 /1 本论文选取在高温气体动力学中具有重要意义的气体非平衡解离和电离动力学作为研究对象，包括两部分内容。

This paper calculated the fast neutron flux of some places in different HFETR cores, such as the 13 ion chamber and L12 fuel rod in the 1 core, the 12 ion chamber and the 1QS ion chamber in the 68-Ⅱ core. Comparison of the calculated and the experimental results was made. It showed that the result was accurate.

用MCNP4C程序分别计算了高通量工程试验堆首炉13电离室和L12元件、第53-Ⅰ炉13电离室和7电离室、第68-Ⅱ炉12电离室和1QS的快中子注量率并与实验测量值比较，计算结果是可靠的。

Main contents and conclusions are: 1 The ionization current was measured continuously by a charge-integration method with a computer after the introduction of radon into the chamber.

主要内容及结论：1充氡后利用计算机连续进行电离电流累积测量，得到了精细的电流随时间的变化曲线，可清楚看出氡及其子体的生成衰变造成的电离电流的生长—稳定—衰减过程，与理论计算值进行了比较，由电离电流衰减速度的变化得出氡吸附作用的影响，并测量到电离室冲洗后氡的反扩散现象；2由已知活度的标准源定出相对测量的刻度系数K值，K=24.62 Bq／pA，对同一个监测源以半年为周期进行多次测量后得出稳定性符合要求；3通过测量电离电流和气压的关系曲线以及不同气压下的饱和曲线，确定了常规的工作条件；4测量了盐酸清洗电离室内表面降低本底的效果；5不确定度分析表明相对测氡的扩展不确定度(k=2)小于5％，由本底涨落得出探测下限为0.5 Bq；6理论上对壁损失修正进行了计算，实验上保持电离室工作在饱和区的情况下，测量了不同气压下电离电流的变化，从中得出了壁损失随气压变化的规律，可以看出，电离电流的实测值和计算值随气压变化规律基本一致；当气压大于125 kPa时，端效应等其它因素造成的影响不大于2％，因而在此工作条件下，测量电离电流后通过计算修正壁损失可以实现近似的绝对测氡，提出了进一步提高绝对测量准确度的方法。

A prediction model has been proposed to deal with threshold voltage shift as a function of 1MeV neutron flux and gate oxide thickness, and to deal with room-temperature annealing of threshold voltage shift induced-by 〓Coγ as a function of electric field and gate oxide thickness. The commonness and individuality of MOS device degradation between hot-carrier effect and ionizing radiation were investigated. The dependence of substrate current, gate current and threshold voltage shift due to hot-carrier on gate oxide thickness were simulated with MEDICI-2D simulator. The photocurrents of PN junction and bipolar transistor were studied. Their transient responses on varied bias voltages, pulse durations and absorbed doses were simulated. The influences of NPN base width on base and collector photocurrents were investigated. We also studied 1MeV neutron displacement damage in PN junction, and calculated reverse current leakage under the neutron flux of 2. 67×10〓 per square centimeter. 3 The study of nondestructive screening method for MOS radiation tolerance A theoretical and experimental study of nondestructive screening methods for radiation tolerance of nMOS and pMOS were firstly fulfilled. We determined the informative parameters pertinent to the method and proposed how to deal with experimental data and verify obtained results statistically, as well as make the required steps for nondestructive screening. Based on the experimental data of 180 samples of discrete pMOS devices, the relation between sample quantity and correlation coefficient, screening equation, and other significant results were obtained from the threshold voltage shifts of pre-and post-irradiation samples.

二、分立器件电离和位移辐射损伤响应研究在国内首次开展了电离辐射引起的氧化层阈值电压漂移和退火理论研究，编程计算了1MeV中子引起的MOS器件阈值电压漂移与中子通量及栅氧厚度的关系，计算了〓Coγ光子引起的阈值电压漂移及退火的时效曲线与纵向电场和栅氧厚度的关系等，对评估MOS型集成电路电离损伤和加固方法研究，以及论文中开展的MOSFETs无损筛选方法研究奠定了基础；分析了MOS器件热载流子损伤效应与辐射电离损伤效应之间的异同性，利用二维模拟软件MEDICI-2D模拟了衬底电流和栅电流，在不同栅氧厚度下随栅压的变化曲线，计算了热载流子效应造成的阈值电压漂移，研究结果对当前存在的以热载流子效应研究取代电离辐射损伤实验研究的设想，具有重要的参考价值；开展了PN结和双极晶体管电离光电流研究，计算了不同偏压、不同辐射脉宽和不同吸收剂量下PN结光电流的瞬时响应，计算了不同辐射脉宽下NPN晶体管基极电流和收集极电流的瞬时响应，以及基区宽度对NPN晶体管光电流的影响，研究结果对双极器件抗电离辐射损伤响应及加固方法研究具有重要意义；在国内首次开展了器件位移损伤的理论研究，分析了辐射产生的缺陷对电性能的影响，计算了注量为2.67×10〓cm〓的1MeV中子产生的缺陷对PN结反向电流的影响。

Simultaneously, the exports of ionization rate and nonionzed concentration are set up as a powerful tool for studying thoroughly the freeze-out effect. dN〓/dp and dN〓/dn are neglected in the linearized equation system of the iteration methods of Newton and Gummel, due to having lower 15 orders or more than dN〓/dn and dN〓/dp, thus the computing effort is cut down with no effect on precision. A new cut-off technique is adopted to accelerate the convergence speed, about twice reduced for Newton iteration method and six times or so for Gummel iteration method. The approximate formulae of Fermi-Dirac statistics are also put forward with simpler form and higher precision. 3. A term dependent on time is added to the electron and hole current succession equations respectively. It is only this model that conservation of charge in transient analysis and alternating small-signal analysis at low temperature can be kept by. 4. The performance of SE-PISCES is explained by the simulation example of PISCES-2B, diode.

研究了低温半导体器件模拟的数值方法：对载流子浓度进行了新的归一化；编制了不考虑掺杂所引进的内建电场时的电离率计算程序；由于低温杂质电离率随偏压状态而变化，为此编制了每次求解迭代时的电离浓度计算程序，并将其插入到求解迭代程序中；同时，设置了杂质电离率和未电离杂质浓度的出口点，为更深入地研究冻析效应提供了有力工具；在Newton迭代法和Gummel迭代法的线性化方程组中忽略了dN〓/dp、dN〓/dn，是因为它们比dN〓/dn、dN〓/dp低15个数量级以上，这样减小了计算量又不影响模拟精度；对Newton迭代法和Gummel迭代法采取了新的截断技术，提高了收敛速度，Newton法迭代法和两次左右，Gummel法减少六次左右；给出了表达式更简单而精度更高的Fermi-Dirac积分近似计算公式。

In this paper we address the question of the transition between autoionization that prevails in small molecules, and delayed ionization occurring in larger molecules or clusters. This transition is illustrated by autoionization of Na2 Rydberg states on one hand, delayed ionization in fullerene C60, and delayed detachment in small cluster anions on the other hand.

本文通过Na2的里德堡态的自电离，富勒烯C60的延迟电离，阴离子小团簇的延迟解离研究了在小分子中起主导作用的自电离和在大分子以及团簇中出现的延迟电离之间的转变过程。

At typical plasma conditions (such as a temperature of 10eV and a density of 0.0016g/cm〓), these autoionization widths are larger than corresponding Doppler and Stark widths by a factor of two or three.

研究了O Ⅲ离子基组态2s〓2p〓和第一激发组态2s2p〓所形成的谱项的内壳层光电离过程，由光电离截面所展现的共振结构，确定了1s-2p内壳层激发态的自电离宽度，结果表明，在某些典型的氧等离子体条件，自电离共振展宽是等离子体中主要的谱线展宽机制。

A number of v=0~57 vibration levels were determined and assigned. The levels cover more than 99% of the potential well depth of the state. No evident autoionization was found related to the levels belonging to the 13 g- state above the ionization threshold, implying the distinct character of the doubly excited valence state from the Rydberg states.

并发现13 g-态能级即使超过电离限时亦无明显的自电离倾向，反映了双电子激发态不同于里德堡态的独特性质。13 g-态是碱金属双原子分子电离限以下唯一的3 g-对称性的态和电离限下唯一较纯的双电子激发态，这些结果为分子结构和量子化学的定量研究提供了重要的信息；（2）通过检测Na 3d 3p原子荧光，观察到Na2分子的33 g和43 g+态在3s+3d解离限以上的预解离能级及其转动线宽加宽等。

It shows that The correlation between the two outgoing electron and the ion play a more important role in the mechanism of this ionization. 2. The auger and the autoionization process of the inner shell are theindirect processes of the ionization that correspond the relaxation and the double excitation of the inner shell. Taouil et 〓 guesses that these processes are included in the mechanism of the ionization. The present theoretical results showthat the influences on the inner shell ionization of these processes are notimportant.

说明在内壳层的高非对称的动能区域，被电离电子与离子以及末态两个电子之间的角关联在这个电离动力学机制中扮演了重要的作用 2、内壳层的饿歇过程和自电离过程为间接电离过程，对应于碰后相互作用的离子弛豫和内壳层的双激发，Taouil et al的实验〓认为包括在电离的机制，我们的计算表明它们对内壳层(e，2e)反应的影响并不很重要。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。