ETUDE PAR RESONANCE PARAMAGNETIQUE ELECTRONIQUE DE LA PHOTOSENSIBILISATION DES ACIDES AMINES PAR LA PROFLAVINE

Abstract— –The photosensitization of amino acids by proflavine is studied using the technique of electron spin resonance spectroscopy. The analysis of the line shape as a function of the incident microwave power (both in the presence and absence of oxygen) and the dependence of the numbers of free radicals on the intensity of the incident light allow one to suggest that two types of radicals are formed. One is formed by a biphotonic process, the nature of the radicals being the same as in the case of ionising radiation, while the other is probably the RO₂ radical formed as a result of photodynamic action.     

Ferrimagnetic coupling in oxamido-bridged Mn(II)Cu(II) compounds: a combined CASPT2 and DDCI study

Multiconfigurational perturbation theory (CASPT2) and difference dedicated configuration interaction (DDCI) are applied to study the ferrimagnetic coupling in an oxamido-bridged Mn(II)Cu(II) molecular species. CASPT2 reproduces the experimental coupling very well. From the partition of the CASPT2 energy, the most important contributions to the coupling are established. Spin populations are calculated with DDCI. The successive improvement of the N-electron wave function allows us to analyse the contributions to the spin delocalization.     

Forward scattering theory of electric-field-gradient-induced birefringence

We attempt to resolve the discrepancy between the Buckingham—Longuet-Higgins (BLH) and Imrie—Raab (IR) theories of linear birefringence induced in a gas of dipolar molecules by an electric field gradient. To this end we present a new calculation of the effect, based on forward scattering of a light beam incident on a thin lamina of gas molecules. We work to electric quadrupole—magnetic dipole order. The beam undergoes a time delay which is proportional to the thickness of the lamina and the electric field gradient, and can therefore be interpreted in terms of a contribution to the refractive index of the gas due to the field gradient. The birefringence is obtained by considering appropriate polarizations of the incident beam. To avoid the occurrence of a divergent quantity, such as appears in the BLH theory, it is essential to take account of the finite beam width. Calculations are performed using both primitive (traced) and traceless molecular quadrupole moments; as required on basic grounds, these results are equivalent. They are also identical to the BLH result. By contrast, the IR result is physically unacceptable because it is not invariant with respect to the use of traced and traceless moments. The source of error in the IR theory remains unclear.     

On the theory of the Buckingham effect

We apply general arguments (based on spatial transformation properties, intrinsic symmetry and dimensional analysis) to the theory of the Buckingham effect (electric-field–gradient-induced birefringence in a gas). These yield, in a simple manner, the temperature-dependent and temperature-independent terms in the birefringence (each to within a numerical factor), and also the expression, derived by Buckingham and Longuet-Higgins, for the effective quadrupole centre of a molecule. We show in addition how the calculation of the two numerical factors can be simplified in our approach.     

A Popov-theory-based approach to digital H{infty} control with measurement feedback for Pritchard-Salamon systems

In this paper, we deal with the digital output-measurement-feedbackH control problem for Pritchard-Salamon infinite-dimensionalsystems with unbounded input and output operators. A discretePopov-theory-based solution is given in terms of the solvabilityof Kalman-Szegö-Popov-Yakubovitch systems associated withthe equivalent discrete-time time-invariant system obtainedby lifting the T-periodic continuous-time system.     

宽波段多步激发K_2-系统产生的钾原子高位态辐射

本文首次报道以690.0～715.0nm宽波段范围内任何波长的脉冲染料激光激发K_2—K系统,由高位钾分子与钾原子碰撞以及分子-原子的混合激发等过程而产生钾原子404.4,404.7和470.05～590.0nm波段内高位态辐射的实验结果,并对激发机制进行了探讨.     

蒙药新-Ⅱ中微量硒的测定

采用硒 -硫氰酸钾 -罗丹明 B-明胶 - OP体系分光光度法测定蒙药新 - 中微量硒。其含量为 6 .6—7.3μg· g-1 ,回收率为 94 %— 95 %。     

Ho2(Co,Si)17化合物的结构与磁晶各向异性

用三弧Czochralski法和真空电弧熔炼法制备了Ho2Co17-xSix化合物.通过X射线衍射和磁性测量手段研究了化合物的结构与内禀磁性.重点讨论了磁晶各向异性和自旋重取向转变.实验结果表明,Ho2Co17为Th2Ni17型六角结构,在0.5≤x≤3的化合物均为Th2Zn17型菱方结构,能够获得单相2:17型化合物的最大Si含量是x=3.在x≤2的浓度范围,化合物的易磁化方向垂直于c轴.随Si含量增加,化合物的居里温度和Co原子平均磁矩单调减少.根据Ho2Co17-xSix化合物的居里温度和自旋重取向温度,获得了磁相图.根据热磁曲线,确定了温度补偿点.在Ho2Co17化合物中观察到了在1005 K发生自旋重取向转变.     

79Kr高自旋超形变的观测

通过５５Ｍｎ（３０Ｓｉ,αｐｎ）反应布居了７９Ｋｒ的高自旋态．用ＧＡＳＰ阵列配以由４０个ΔＥ×ＥＳｉ（Ａｕ）望远镜所组成的带电粒子球实现γγγ－带电粒子符合测量．观测到由相对强度为（２．７±０．３）％的８条级联γ跃迁所组成的７９Ｋｒ高自旋超形变转动带．除了在转动频率ω＞０．９５ＭｅＶ处急剧下降外,该带的动力学转动惯量近乎常数（22ñ2／ＭｅＶ）并被解释为具有四极形变参数β２＝０．５１以及本征侵入组态为π５０ν５１． High-spinstates in 79Kr were populated via the fusion evaporation reaction 55Mn (30Si,αpn)at 130 MeV.Promptγ γγ charged particle coincidences were measured by using the GASP array in conjunction with the ΔE×E Si(Au) charged particle ball.Asu perdeformed band consisting of 8 γ ray transitions with an intensity of (2.7±0.3)% has been indentified in 79Kr.The dynamic moment of inertia for the band is nearly constant at approxately 22ñ2/MeV below arotational frequency of 0.95 MeV...