渐进因子分析－pH－分光法测定多元酸的离解常数

根据多元酸平衡体系中型体具有先出现先消失的特点,提出了用渐进因子分析与化学平衡结合迭代,从pH-分光矩阵中求解多元酸离解常数的新方法。用该法测定了多元酸茜素S和铬天青S的离解常数,并讨论了确定型体存在区域的经验式。结果表明该方法稳定、可靠、算法收敛快,所测得的离解常数与文献值吻合。     

1,4-苯并二氮杂-2-酮的电荷转移性质

本文用分光光度法测定了标题化合物分别与TCNE和对甲苯酚钾形成的电荷转移络合物的电子跃迁能hvcr并计算了它们的电子亲合力(E_A)和电离势(I_p),还测定了络合物的热力学常数(K,ΔH,ΔS)。结果表明,该化合物不但可以作为电荷受体,也可以作为电荷给体。处于分子7位取代基的Hammett常数σ与hv_cr(或ΔH)有线性关系。     

毛细管电泳电化学检测法同时测定三种氨基酸的电离常数

利用自制微圆盘铜电极,建立了一种毛细管电泳电化学检测同时测定色氨酸、丝氨酸和半胱氨酸pKα值的新方法。在不同pH条件下测定各氨基酸的有效淌度（μeff）,利用Origin软件对μeff-[H^＋]按理论关系式进行非线性拟合,得到其pKα值。该方法简便、快速,测定值与文献值符合良好。     

355nm激光作用下丁酮多光子电离质谱信号分析

为研究由氢键形成的超分子体系内的质子化构型,利用355nm共振增强多光子电离(REMPI)技术结合飞行时间质谱(TOF-MS)得到丁酮多光子电离系列团簇质谱.实验没有观测到丁酮母体的团簇信号,只测到丁酮解离、异构后的异丙醇团簇离子,为丁酮解离、异构提供了很有意义的实验数据.     

NO分子共振增强的多光子离化机制

用皮秒Nd：YAG激光器泵浦光学参量发生／放大器做激发源,获得了420～480nm波长范围内NO分子的多光子离化谱。通过对谱线的归属,分析确定了NO分子的离化为以A^2∑为中间共振态的(2 2)共振增强的多光子离化过程。以速率方程为基础,利用激光脉宽较窄(35ps)的条件,推导出离化信号随激光强度呈近四次方变化关系,与实验测量结果相符,这可为用共振增强多光子离化(REMPI)光谱技术探测污染物NO分子提供实验参考。     

Calculation of the 1s–2s two-photon excitation cross-section in atomic hydrogen

The two-photon excitation cross-section of atomic hydrogen is calculated using explicit summation over intermediate states within the framework of dipole approximation. The matrix element for two-photon excitation is transformed into finite sums, consisting of the product of a radial and angular part. Nine intermediate states are employed in the calculation of the transition matrix element. The two-photon excitation cross-section obtained for the transition 1s ²S_1/2–2s ²S_1/2in atomic hydrogen is a good agreement with the literature.     

Tungsten L transition line shapes and energy shifts resulting from ionization in warm dense matter

Spectra of the W L transitions in the energy range 8–12 keV from warm dense plasmas generated by the Naval Research Laboratory's Gamble II pulsed power machine were recorded by a newly developed high-resolution transmission-crystal X-ray spectrometer with ±2 eV accuracy. The discharges have up to 2 MV voltage, 0.5 MA current, and produce up to 2.4 MJ/cm^?3 energy density. The plasma-filled rod pinch (PFRP) diode produces a plasma with N_e ≈ 10²² cm^?3 and T_e ≈ 50 eV during the time of maximum X-ray emission. By analyzing the line shapes, it was determined that the Lβ₂ inner-shell transition from the 4d_5/2 level was shifted to higher energy by up to 23 eV relative to nearby Lβ transitions from n = 3 levels. In addition, the Lβ₂ transition was significantly broader and asymmetric compared to the n = 3 transitions. The energy shift of the Lβ₂ transition results from the ionization of electrons outside the 4d shell that perturbs the transition energies in the ions to higher values. The increased line width and asymmetry result from unresolved transitions from a range of ionization states up to +28. The ionization distribution was determined by comparison of the measured energy shifts and widths to calculated transition energies in W ions, and the ionization was correlated with Gamble discharge parameters such as the anode type and the high voltage delay time. This work demonstrates a new hard X-ray spectroscopic diagnostic technique for the direct measurement of the ionization distribution in warm dense plasmas of the heavy elements W through U that is independent of the other plasma parameters and does not require interpretation by hydrodynamic, atomic kinetics, and radiative simulation codes.     

(1+2+1)双共振多光子电离概率的理论研究

共振增强多光子电离光谱技术已成为研究原子、分子高激发态能级结构的重要方法。运用光和物质相互作用的速率方程理论,推导出四能级物质系统1+2+1双共振增强多光子电离概率的解析表达式,以此为基础,理论模拟了电离概率随激发光强、激光脉冲宽度和碰撞弛豫速率的变化,发现在1+2+1多光子电离机制中,电离概率随光强的增加而增大,继而出现单步、双步激发饱和的现象,直至饱和值1;继续增大光强,电离概率将围绕饱和值1窄幅振荡,振荡幅度随光强增加而增大。随激光脉冲宽度的增大,电离概率从零开始逐渐增大直至饱和值1。而随碰撞弛豫速率的增大电离概率以线性规律减小。     

重复频率高功率微波脉冲的大气击穿

 理论研究了重复频率高功率微波脉冲在大气中的传输特性,推导了n个高功率微波脉冲之后空间某点的电子密度,数值模拟并给出了在不同微波频率、大气压强、脉冲宽度以及脉冲间隔的条件下,大气击穿时,透射过去的脉冲个数与微波功率的关系。模拟结果表明：当微波脉冲参数一定时,压强越小,透射过去的脉冲个数越少,大气越容易发生击穿;当压强一定时,脉宽越宽,微波频率越小,透射过去的脉冲个数越少,大气越容易发生击穿。     

基于微热板表面离子化源的离子迁移率谱仪研究

根据表面离化机理和离子迁移率谱检测方式,设计和制备了一种基于表面离化源的离子迁移率谱仪(IMS)。表面离化源为采用微机电系统(MEMS)工艺加工的微热板阵列,除了作为离子产生器,还作为漂移管的一个离子栅,用以实现离子向漂移区的注入。测试了该IMS对三乙胺的响应特性并研究了离子注入时间对离子迁移率谱的影响。结果表明,基于微热板表面离化源的离子迁移率谱仪对三乙胺具有很好的动态响应特性,三乙胺浓度的平方根与离子峰面积具有较好的线性关系,检出限可达6×10-8(V/V)。此外,与传统的放射离化IMS相比,这种IMS还具有离子注入时间短和离子迁移率谱基电流为零等特点。