SYSTEMATIC STUDY OF POLARIZATION OF TWO-PHOTON ABSORPTION IN SYMMETRY ASSIGNMENTS

In this paper, we have systematically analyzed the degenerate and nondegenerate two-photon polarization ratios of various point groups. We present the maximum of symmetry assignments of two-photon transition with the combination of degenerate and nondegenerate two-photon absorption. These results provide the theoretical basis for the experimental assignments.     

光学多道分析仪及其应用

光学多道分析仪是七十年代发展起来的一种光谱同时探测仪器.光谱信息的获取通常有两种方式:一是对感兴趣的波段进行依次扫描,二是对该波段进行同时探测.前者是以出缝-光电倍增管组合的方法为代表,后者则是以光谱干板的应用最为广泛.但是,这种同时探测器的灵敏度低,转换特性一般不呈线性(即乳剂特性γ≠1),其准确度和精密度也很差,波长定标比较麻烦.而且,所收集到的光谱信息只有在感光板显影后才能证实其有效性,因此常常会失去非常宝贵、且难以重复的实验数据.为了同时探测全波段光谱,近二十年发展了两种测试技术:一种是多路探测技术,即阿达…     

气相吡啶分子S1态的(2+3)偏振共振多光子电离谱研究

利用气相吡啶分子分别在圆偏振光激发和线偏振光激发下的（２＋３）偏振共振多光子电离（ＰＲＭＰＩ）谱,对其第一激发态（Ｓ１）上的振转结构进行了研究。在谱中观察到了呈双峰结构的电子振转跃迁谱带。分析表明,所有振动谱带均为Ｓ１态上Ｖ６ａ、Ｖ１０ａ、Ｖ１２、Ｖ１６ｂ和Ｖ１７ａ以及基态上Ｖ９ａ的混合频率谱带。旨认吡啶Ｖ１７ａ的Ｓ１态频率为６７０ｃｍ＾－１,并认为在Ｓ１态上Ｖ７ａ频率降低的原因与Ｖ１０ａ类似。     

InCl分子C1Π1态光谱研究

采用激光诱导荧光技术对InCl分子C1Π1→X1Σ+荧光光谱进行了分析和归属, 在发射谱中探测到ν′=1向下的跃迁, 证明C态预离解只能发生在ν′=1之上。 并对C1Π1→X1Σ+的荧光衰变曲线进行了观测, 得到InCl分子C1Π1(ν′=1)态的无碰撞辐射寿命τ0≈11 ns及电子跃迁矩|Re|2≈5.95D2。     

三(2-苯并咪唑甲基)胺-锌(Ⅱ)配合物模拟水解酶催化酯类水解研究

研究了三(2-苯并咪唑甲基)胺-锌(II)配合物作为水解酶模拟物催化乙酸对硝基苯酯(NA)水解动力学.结果表明,催化水解速率对NA及配合物浓度呈一级反应.水解速率遵循速率方程v=(k_cat[Zn]＋k_OH[OH^－]＋k₀)[NA].在298K,I=0.10mol/LKNO₃,0.02mol/LTris,40％CH₃CN水溶液中,二级反应速率常数k_cat和k_OH分别为0.12、1.45mol^－1·L·S^－1,k₀为NA溶剂解的速率常数,其值为3.70×10^－6s^－1.与10％CH₃CN溶液中的k₀值相比,40％CH₃CN水溶液中的k₀值明显降低.本研究表明三(2-苯并咪唑甲基)胺-锌(II)配合物能有效地催化NA的水解.配合物对NA水解的催化作用受酸碱平衡控制.根据实验结果提出了催化反应的机理.     

用解卷积方法测量亚毫微秒荧光寿命

本文报道了用光电倍增管及取样示波器测量Rh6G和不同浓度的KI混合水溶液的荧光衰变曲线。系统的响应时间是毫微秒量级的,测量得到的衰变曲线是溶液的真实衰变曲线与仪器响应函数卷积的结果。应用相平面法与迭代卷积法相结合来进行解卷积处理,求得溶液的真实荧光寿命,其结果可获得最小时间分辨为130ps,达到仪器的响应函数半宽度的3％。     

亚毫微秒脉冲染料激光器的瞬态过程的研究

本文报导一种N_2激光器泵浦的亚毫微秒弛豫振荡脉冲染料激光器.用实验观测了其弛豫振荡及亚毫微秒脉冲的形成过程,并根据振荡的瞬态过程不同阶段,采取分别求速率方程组近似解的方法,对其工作过程进行了理论分析.将有关参量和实验测量值代入这些解,所估算的脉冲宽度数量级与实验显示值能较好地相符合.     

CW Nd:YAG THERMO-STABLE RESONATORS OPERATING IN POWER-STEADY STATES

There are two dynamical stable zones in the operation of solid laser containing a thermal lens. In this paper, we point out that in the two stable zones two kinds of dynamical stable states can exist in a laser resonator: mode-steady thermo-stable state and power-steady thermo-stable state. They are different from each other in general. The operating conditions for power-steady thermo-stable state are presented. A cw Nd: YAG thermo-stable resonator operating in power-steady states has been designed, and 40 W TEM₀₀ output power in 1.06μm is obtained experimentally.     

EFFECT OF THE LASER TRANSVERSE SPATIAL DISTRIBUTION ON MULTIPHOTON IONIZATION PROCESSES

In this paper, the dependence of the photoionization cross section σ₂, total ion number N_i and the FWHM of photoionization spectral line in resonant multiphoton ionization processes(RMPI) upon the parameter C of the laser transverse spatial distribution has been studied. Considering the effects of spatial coordinate on the resonant multiphoton absorption cross section σ₁, the limited dimension of the laser-molecular interaction volume and threshold of laser intensity for RMPI, we deduce the expression of σ₂ vs the parameter C. We calculated the value of σ₂ for (2+2)PI of benzene by numerical method, and com-pared the result with that obtained by Bruzzeste et al. In additon, we also present the total ion number of photoionization and the FWHM of photoionization spectral line as a function of the parameter C.