线性多烯分子的共振拉曼光谱

线性多烯分子是重要的光电材料,它还具有光采集、 光防护、 防癌、 抗癌功能,也是物理学、 化学理论研究的理想分子。 共振拉曼光谱是研究线性多烯分子最有力的工具。 本文总结了线性多烯分子共振拉曼光谱的特征及其与分子结构的关系,包括：电子光谱(紫外-可见吸收光谱)、 拉曼光谱的性质及与外场的关系;电子能隙对碳碳原子振动的调制作用;给出几个实验结果：温度降低、 溶剂密度增加、 溶液浓度降低等会使线性多烯分子结构有序增加,π电子能隙减小,使紫外-可见吸收光谱红移;π电子离域扩展,有效共轭长度增加,拉曼活性提高,拉曼光谱红移,拉曼截面增加。 振幅模型是研究线性多烯分子较理想的模型。     

共振拉曼效应和电子-声子耦合对线性多烯分子共振拉曼光谱的影响

线性多烯分子具有高强度且信息丰富的共振拉曼光谱,在生物学、光电材料和医学等方面都有一定应用.而含有共轭双键的短链β胡萝卜素分子是多烯分子中极具有代表性的分子.在激发光作用下π电子与CC键振动相互作用影响着吸收光谱和拉曼光谱,而共振拉曼效应和电子-声子耦合影响着共振拉曼光谱的强度、频率和线型.测量了β胡罗卜素分子在二氯乙...     

溶剂密度对β胡萝卜素拉曼散射截面的影响

测量了含有9个CC共轭双键的链状多烯类生物分子β胡萝卜素在9种溶剂中的紫外—可见吸收和拉曼光谱.结果表明,β胡萝卜素C—C,CC键拉曼散射截面随溶剂体密度增加而线性增加,其机理是β胡萝卜素分子在体密度大的溶剂中受浮动干扰小,分子结构有序性高,π电子离域扩展,产生强的相干弱阻尼CC键振动,而产生大的拉曼散射截面.密度对分子拉曼散射截面影响研究还没见过报道,本文为多烯类链状分子的光散射理论研究提供了实验线索,也对多烯类链状分子性能研究及光电器件研制有参考价值. 关键词： 拉曼散射截面 多烯分子 吸收光谱 分子结构有序     

液芯光纤方法研究溶剂对分子拉曼光谱强度的影响

液芯光纤可以大幅度提高拉曼光谱强度. 本文用液芯光纤方法测量了CCl4 在CS2 和C6H5Br中不同浓度下459 cm-1,314 cm-1和218 cm-1的拉曼光谱强度,验证了一些溶剂使某些分子拉曼光谱增强的溶剂效应.     

共振拉曼光谱在体测量类胡萝卜素含量

类胡萝卜素是人体内重要的抗氧化剂,能够消除体内的自由基和其它有害氧分。研究表明类胡萝卜素含量与癌症、心血管疾病、老化等疾病发病率呈反比关系。目前检测方法为采用血清液相色谱检测方法,不能做到在体无损伤、实时测量。文章介绍了一种用于测量类胡萝卜素的新技术——共振拉曼光谱技术,具有在体无损伤、灵敏度高和实时检测等特点。该技术利用强度远小于美国ANSI Z136.1-2000标准的473 nm激光激发拇指中类胡萝卜素,产生强荧光和叠加在其上的弱共振拉曼光,通过测量拉曼散射光强度在体评估类胡萝卜素的含量。同时,利用组织通透技术,改善了测量信噪比。测量了不同饮食习惯志愿者的类胡萝卜素含量,说明其含量与其摄入量成正比。该技术在临床应用和科学研究等领域具有重要意义。     

分子间费米共振增强二元溶液体系的受激拉曼散射研究

研究了液芯光纤内不同体积比的甲苯和间二甲苯二元混合溶液的受激拉曼散射.实验结果表明:在不同的体积比之下二元溶液的环呼吸振动模式1002 cm^-1,甲基的CH伸缩振动模式2920 cm^-1 以及芳香环CH对称伸缩振动模式3058 cm^-1的拉曼带同时产生受激拉曼辐射,并且2920 cm^-1 和 3058 cm^-1 拉曼带的一阶受激拉曼散射阈值要低于1002 cm^-1拉曼带的二阶 关键词： 分子间费米共振 二元溶液 受激拉曼散射 拉曼散射截面     

柞蚕丝蛋白分子的拉曼光谱研究

本文首次记录了作了柞蚕丝样品的拉曼光谱,讨论了拉曼光谱数据与红外光谱数据之间的差别,计算了拉曙谱中酪氨酸残基费米共振双线的相对比。结果表明,柞蚕丝蛋白分子中的酪氨酸残基为“露型”。     

不同构型罗丹明分子拉曼光谱的密度泛函理论研究

利用密度泛函理论研究了罗丹明6G、罗丹明123和罗丹明B分子的拉曼光谱. BP86泛函计算的罗丹明系列分子的阳离子在气相中的拉曼光谱与相应的分子在水溶液中的实验光谱符合很好. 结果显示氯离子以及氢键的引入对罗丹明B分子的拉曼光谱有较明显的影响,该影响可以部分地解释罗丹明B分子在水溶液中和在金表面上拉曼光谱的不同. 精确描述罗丹明分子在金属表面的表面增强拉曼光谱,需要考虑由界面相互作用而导致的变化.     

Anomalies in the polarized raman spectrum of crystal quartz

Summary By means of coherent Raman scattering we have measured in quartz the dispersion of the elements of the Raman tensor in the range (900÷1070) cm⁻¹. The results determine with good accuracy the relative contribution of the various modes to the second-order nonlinear susceptibility. For some elements of the Raman tensor the present results greatly improve the precision of data already known; for others the dispersion and the relative strengths have been measured for the first time. In particular, a strong, frequency-dependent, asymmetry of the Raman tensor has been evidentiated; this asymmetry is interpreted in terms of optical Raman activity.     

Vibronic scheme of the franck-condon state of F centers that consistently elucidates MCD and resonance raman scattering

Abstract

The resonance Raman scattering (RRS) of F centers, particularly the photon-energy dependence of linear polarization of the RRS, has been studied on the basis of a vibronic viewpoint. With combinination of previous results that have explained magnetic circular dichroism (MCD) spectra, a vibronic scheme of the Franck-Condon state of F centers for KCl, KBr and KI crystals is established.     

Effect of non-magnetic impurities on the observation of superconducting gap excitations by raman scattering

The effect of small concentrations of non-magnetic substitutional impurities (characterized by changes in mass, nearest neighbour force constants and local electron-phonon interaction) on the observability of superconducing (sc) gap excitations in 2H-NbSe₂ by Raman scattering is considered within the theoretical framework of Balseiro and Falicov (bf). The phonon self-energy when evaluated forq=0 using the Einstein oscillator model for the host phonons is seen to have a pole corresponding to the impurity mode besides the gap excitation one around 2Δ previously obtained bybf. A splitting of the impurity mode into two in thesc state is predicted. An enhancement occurs in the strength of thesc gap excitation peak whenever it is close to the impurity mode. The data from the experiments of Sooryakumar, Klein and Frindt on impure samples of 2H-NbSe₂ are discussed in the light of the present calculation. Preliminary results of this paper were presented by one of us (snb) at the International Conference on Phonon Physics at Indiana University, Bloomington, USA, in August-September 1981.     

Solvent effects on the static nuclear relaxation and the curvature hyperpolarizabilities of push-pull polyenes

The influence of the solvent on the nuclear relaxation and curvature contributions to the first, β, and second, γ, hyperpolarizability, of push-pull molecules has been investigated within the framework of the valence-bond charge-transfer model and the analytical evaluation of electrical properties method. It was found that the solvent effect on the β and γ values is very pronounced, where increases of a factor as great as 15 for cyanine resonance form and 30 for zwitterionic and neutral resonance forms, were calculated upon changing from gas phase to an aqueous environment. The general trends of β and γ in different environments may be estimated roughly by adding the harmonic terms of the nuclear relaxation to the electronic contribution because the anharmonics terms of the nuclear relaxation and the contribution of curvature tend to cancel one another.     

钠分子的共振喇曼散射

本文用80mW6238.2(?)的He-Ne激光激发钠蒸气,用一种新颖的棱镜反射光路,从后向首次观察到了56O0～8200(?)钠分子的共振喇曼谱.     

Solvent polarity scales: determination of new ET(30) values for 84 organic solvents

The solvent polarity parameter E_T(30) is newly measured from the solvatochromism of the betaine dye 30 for 84 solvents and re‐measured for 186 additional ones. The results are organized in a database. It is shown that the validity of linear solvation energy relationships used for the determination of secondary E_T(30) values is limited to non‐hydrogen‐bond donor solvents. Relationships with the chain length n are given for the determination of tertiary E_T(30) values of the homologous H(CH₂)_nY solvent series. The parameter E_T(30) is orthogonal to the function of the refractive index (n² ? 1) / (2n² + 1). For non hydrogen‐bond donor solvents, this allows to enter E_T(30) as an almost pure electrostatic parameter in a new linear solvation energy relationship. Copyright © 2014 John Wiley & Sons, Ltd.     

利用喇曼光谱测量氧碘化学激光器氯气利用率的实验研究

 介绍了利用自发喇曼散射光谱测量氧碘化学激光器单态氧发生器氯气利用率的原理及实验装置，并给出了在以氮气作为稀释气的0.1mol/s射流式氧发生器上测试的结果，测试相对误差小于12%。由于该方法只需要通过测量喇曼谱线相对强度之比，即可算出氯的利用率，因此不需要另外的标定实验，从而避免了因标定带来的影响。该方法减小了测试误差，简化了实验过程，提高了测试效率。     

Volume dependence of the raman frequencies in Y Ba2Cu3Ox single crystals with different oxygen content

Abstract

The Raman spectra of Y B _a2C_u3O_x, single crystals (x=6.25; 6.75; 7.0) were measured at pressures up to 22 GPa (35 GPa for x=6.25) at room temperature in nearly hydrostatic conditions. The frequency-volume curves for most of the Raman-active fundamental vibrations were derived from the present data making use of a previous high-pressure study of the equations of state of Y Ba₂ Cu ₃ O _x compounds.