HCl分子在激光场中的多光子激发

用二次量子化方法讨论了ＨＣｌ分子在激光场中的多光子激发，还包括对ＨＣｌ分子伸缩振动能级的计算，跃迁概率随外场频率的变化及随时间的变化（取光场强度１０~（－８）Ｗ／ｃｍ~２）。     

两种实现选择激发方法的比较

在无波形发生器的情况下，利用可变衰减器或整形ＤＡＮＴＥ脉冲序列的方法可实现选择激发，通过在ＵＮＩＴＹ－４００ ＮＭＲ谱仪上进行的选择激发实验，比较了这两种方法的适用性，结果表明，整形ＤＡＮＴＥ脉冲序列的方法，应用灵活，方便，不需要对谱仪的硬件作任何改动，并且选择激发的轮廓更接近于理想的情况，若激发谱宽范围较大（＞１０００Ｈｚ），建议采用快速变换衰减器衰减幅度的方法，若激发谱宽范围较小（＜１０００Ｈ     

多光子技术及其应用研究进展

本文综述了多光子技术的基本原理及其在生命科学、化学、物理和材料科学领域的应用研究进展。     

高能量激发的发光材料

从不同材料在高能量密度激发下在激发、传递和发光等不同阶段中的效率变化,了解各种材料在高密度激发时的能量损失的主要环节,分清基质和发光中心的选择原则。为投影电视荧光粉和细管灯粉寻找具有较高效率的发光材料,在X线影像板的光激励材料的研制和γ线影像板的可行性分析方面也得到了一些结果。     

ZnS:Tm的薄膜电致发光及激发过程

用电子束蒸发的方法制备了传统的双绝缘层的ZnS:Tm的薄膜电致发光器件，对其电致发光谱进行分析，在光致发光中，Tm离子受到基质ZnS的无辐射能量传递，而在电致发光中，Tm被过热电子碰撞激发而非能量传递，在所研制的电致发光器件中，稀土TmF3掺杂浓度不同，器件的发光性能也不同，在双绝缘层的ZnS:Tm的薄膜电致发光器件的基础上，改变器件的结构，发现器件的蓝光发射与红光发射之比增加，并对Tm离子可能的发光机理进行了探讨。     

Calculated Plasma Parameters and Excitation Spectra of High-Pressure Helium Discharges

A collisional-radiative model was used to study the kinetics of an atmospheric pressure helium discharge. The electron kinetics was obtained from a two-term solution of the Boltzmann equation with electron–electron collisions included. The distribution of the helium electronic excited states was compared to measured values and used to calculate excitation temperatures. The results show that a unique value of the excitation temperature cannot be used to characterize the whole electronic states distribution, because the plasma is not in local thermodynamical equilibrium under the conditions considered. Other calculated discharge parameters, such as the electron temperature, the maintenance electric field, the density of metastable atoms in the 2 ³ S state, and the ion densities are presented and compared to experimental data when available.     

三角波电流激励示波计时电位法的研究

推导了三角波电流激励波计时的电位方程，讨论了电流幅值、频率和去极剂离子对示波图的影响，并对双电层微分电容的作用进行了详细的讨论，给出了示波端点电位的表达式和理论议程的适用条件。     

强激光场中NO分子多光子选择激发──含时薛定鄂方程的代数解法

报道了在半经典偶极近似下应用二次型非谐振子李代数模型研究强激光场中NO分子的多光子选择激发，并计算了NO分子的跃迁几率．     

Biochemical Aspects of Selenium Amino Acids and Selenium Peptides

Abstract

We discovered peculiar enzymes participating in selenium amino acid metabolism: selenocysteine β-lyase occurring in mammalian tissues and bacteria, and D-selenocystine α,β-lyase occurring in Clostridium sticklandii. We here describe enzymological properties and reaction mechanisms of these enzymes. We synthesized the selenocysteine analogues of Neurospora crassa copper metallothionein as well as four diastereoisomers of glutathione. Their physicochemical properties and reactivity with peroxides are also described.     

Excitation of chemiluminescence in the reaction of benzophenone-O-oxide with diphenyldiazomethane. Quantum-induced decomposition of diphenyldiazomethane

The excitation yield (⌽⁺) of triplet benzophenone in the chemiluminescence reaction of thermal decomposition of diphenyldiazomethane (Ph₂CN₂) was measured. Triplet benzophenone was produced by the reaction of benzophenone-O-oxide with Ph₂CN₂ in a MeCN solution. The ⌽⁺ value is equal to 0.05 and temperature-independent. Analysis of the dependences of the observed rate constant of chemiluminescence decay on the concentration of Ph₂CN₂ both in the presence and absence of a luminescence activator suggests the quantum-induced decomposition of diazomethane in the reaction with triplet benzophenone. The rate constant of the reaction of triplet benzophenone with Ph₂CN₂ was estimated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1097–1101, June, 1999.     

微波等离子体增强辉光放电光源激发温度的研究

研究了一种改进型的微波等离子体增强辉光放电光源在光谱分析中的应用，对其重要的参数指标－激发温度进行了较为较细的考察。结果表明引入微波等离子体后辉光放电的激发温度明显高于单纯辉光放电时的激发温度。     

Examination of the Excitation Performance of Different Capillary Optics

 The use of X-ray optics allows for elemental analysis of small samples and small areas: particles, inclusions and elemental distributions. Previously, collimators have been used to limit the X-ray beam diameter. However, in recent years, glass capillary optics have come into use. X-rays propagate through a capillary optic by total reflection from the inner wall of the capillary. Furthermore, different types of capillary optics, mono-capillary and poly-capillary lenses, with distinct excitation properties are now available. Capillary optics alter the input tube spectrum due to the energy dependence of the critical angle of total reflection. Minimum beam diameter and the energy dependence of the beam diameter are also influenced by the conditions for total reflection. In this paper, the exciting performance of different X-ray optics are examined and compared to collimators.     

稠环芳烃菲电子激发态的含时密度泛函理论研究

用含时密度泛函理论TD-DFT及组态相关CIS、含时TD-HF方法对菲的UV光谱进行了理论研究,在几何构型优化的基础上,计算了其垂直电子激发能．计算表明,基函数的选择对激发能的计算影响较大,而不同的密度泛函交换一相关势对其影响较小,这和轨道能级的系统误差相互抵消有关．对菲的电子跃迁能的计算,与实验结果比较相一致,理论与实验的误差和不同的实验之间的误差在同一个数量级之内,显示TD-DFT方法比CIS,TD-HF方法更适合电子激发能的计算．     

Selective Excitation with Asymmetric Adiabatic Pulses for NMR Spectroscopy

Existing selective pulses are mainly constructed in the forms of classically shaped pulses, such as the Gaussian pulses, or generated by using numerical optimization methods. However, all of these pulses are highly sensitive to radiofrequency (RF) intensity variation, which means their performance is highly dependent on the accuracy and stability of the RF intensity. Even a slight RF intensity deviation can cause severe degradation in the excitation profile. To solve this problem, we propose a method for narrow selective excitation by sequential application of a pair of phase‐opposite asymmetric adiabatic pulses, all within two scans. By retaining the adiabatic character, the new method is highly robust to RF intensity variation. Moreover, it has flexible excitation bandwidth, ranging from line‐selective to narrow‐band‐selective pulses. The method is tested both in numerical simulations and solution‐state NMR experiments.     

Ultrafast fluorescence resonance energy transfer in a bile salt aggregate: Excitation wavelength dependence

Fluorescence resonance energy transfer (FRET) from Coumarin 153 (C153) to Rhodamine 6G (R6G) in a secondary aggregate of a bile salt (sodium deoxycholate, NaDC) is studied by femtosecond up-conversion. The emission spectrum of C153 in NaDC is analysed in terms of two spectra-one with emission maximum at 480 nm which corresponds to a non-polar and hydrophobic site and another with maximum at ∼530 nm which arises from a polar hydrophilic site. The time constants of FRET were obtained from the rise time of the emission of the acceptor (R6G). In the NaDC aggregate, FRET occurs in multiple time scales — 4 ps and 3700 ps. The 4 ps component is assigned to FRET from a donor (D) to an acceptor (A) held at a close distance (R _DA ∼ 17 ?) inside the bile salt aggregate. The 3700 ps component corresponds to a donor-acceptor distance ∼48 ?. The long (3700 ps) component may involve diffusion of the donor. With increase in the excitation wavelength (λ _ex) from 375 to 435 nm, the relative contribution of the ultrafast component of FRET (∼4 ps) increases from 3 to 40% with a concomitant decrease in the contribution of the ultraslow component (∼3700 ps) from 97 to 60%. The λ _ex dependence is attributed to the presence of donors at different locations. At a long λ _ex (435 nm) donors in the highly polar peripheral region are excited. A short λ _ex (375 nm) ‘selects’ donor at a hydrophobic location.     

The Effect of Vibrational Excitation of Molecules on Plasmachemical Reactions Involving Methane and Nitrogen

An experimental study of plasmachemical reaction involving CH₄ and N₂ molecules in rf discharge was studied in order to know the effect of vibrational excitation of N₂ molecules. When the relative nitrogen concentration was greater than 0.8, the main product of CH₄ decomposition was HCN, and the rate of methane decomposition at this condition was faster than that one in pure methane. These results could be confirmed through the mass spectroscopic method. The reason for these results is the vibrational energy of N₂ excited by rf discharge. The chain reaction mechanisms of producing HCN by vibrational excitation of N₂ were examined closely through numerical simulation. The rate-controlling step was the dissociation reaction of excited nitrogen molecule to the atomic nitrogen, so the process of HCN synthesis was limited by the value of reaction constant, k^N.     

Excitation of chemiluminescence in a model reaction of diphenylmethane oxidation. Evaluation of the efficiency and semiempirical calculations

The absolute yields (^*) of excitation of the triplet benzophenone, a product of disproportionation of peroxyls in the chemiluminescent oxidation reaction of diphenylmethane, were measured. The ^* value is independent of the temperature and viscosity of the medium, but decreases with increase in its polarity: it is 0.003 in CCl₄ and 0.0015 in MeCN. Semiempirical MNDO calculations of the structure of intermediates and the energy profile of their decomposition were carried out. A conclusion was made that the excitation of the³n^* state of the ketone occurs during the decomposition of the intermediate tetroxide Ph₂CHOOOOCHPh₂ after the transition state, but before isolation of the Ph₂COOO biradical, which thereafter decomposes to benzophenone and O₂.Dedicated to Professror Waldemar Adam, to his 60th birthday.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2464–2470, October, 1996.