手性物质拉曼光活性研究综述

通过对大量文献的调研，本文分四个部分对手性物质的旋光现象扩振动光活性进行了较为全面的介绍，重点介绍了拉曼光活性ＲＯＡ产生机理、研究状况及对其研究的意义。     

钒氧酞菁多晶薄膜的稳态光电压特性研究

报道了Ａｌ／ＶＯＰｃ／ＩＴＯ夹心结构在稳态连续光照射下的光电压作用谱，稳态光电压作用谱不仅依赖于照射光的波长，而且依赖于ＶＯＰｃ（钒氧酞菁）多晶薄膜的堆积方式，对ＶＯＰｃ在相１，相１１，及α型三种堆积方式的稳态电压波长响应进行了研究，并对其内在机制作了初步探讨。     

拉曼光活性(ROA)经典理论模型研究

拉曼光活性（ＲＯＡ）经典理论模型研究马树国吴国祯（清华大学物理系北京１０００８４）ＡＣｌａｓｉｃａｌＴｈｅｏｒｙｆｏｒｔｈｅＲａｍａｎＯｐｔｉｃａｌＡｃｔｉｖｉｔｙＭａＳｈｕｇｕｏ，ＷｕＧｕｏｚｈｅｎ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，Ｔｓｉｎ...     

SOI无间距定向耦合光开关模型分析及设计

提出了一种简便可行的ＳＯＩ无间距定向耦合光开关（ＢＯＡ型－Ｂｉｆｕｒｃａｔｉｏｎ Ｏｐｔｉｑｕｅ Ａｃｔｉｖｅ）模型分析方法，采用等离子体色散效应这种光开关的电学调制机理；而用ｐｎ结大注入效应分析开拳电学性质；并根据大截面单模ＳＯＩ脊形波导理论和上棕分析，设计了利用双模干淑机制工作的这种器件的结构参数和电学参数。     

GexSi1—x／Si异质结无间距定向耦合光开关模型分析

提出一种简便可行的ＧｅｘＳｉ１－ｘ异质结无间向耦合光开关（ＢＯＡ型－Ｂｉｆｕｒｃａｔｉｎ ＯｐｔｉｃａｌＡｃｔｉｖｅ）。该方法采用等离子体色散效应分析了这种光开关学调制查理；采用异质结超注原理分析了开关的电学性质，并根据曲单模脊形波导理论和上述，设计了利用双模干涉机制工作的Ｇｅ０．０５Ｓｉ０．９５／Ｓｉ异质结ＢＯＡ型光开并的结构参数和电学参数。     

基于2×2光开关的光交换系统研究

本文详细描述了基于光信元（ｐｈｏｔｏｎｉｃｃｅｌ）进行交换的光交换系统模型，讨论了光信元的帧结构方法，并完成了２×２ＬｉＮｂＯ３光开关交换单元实验，其技术性能指标为：工作速率１５５Ｍｂ／ｓ；消光比优于２０ｄＢ；插入损耗小于５ｄＢ     

Spiro－Oxaziue染料掺杂高分子材料光致变色效应的研究

报道Ｓｐｉｒｏ－Ｏｘａｚｉｕｅ染料掺杂高分子（ＳＯ／ＰＶＡ）膜具有很强的可逆光致变色效应，通过对这种高分子膜吸收光谱的测试，证实ＳＯ分子具有二个特征吸收带，一个在３６０ｎｍ，另一个在５９５ｎｍ，分别对应于二个分子异构体ＳＯ１和ＳＯ２，有关这种ＳＯ／ＰＶＡ光致变色过程的研究给出了ＳＯ１对紫外光和ＳＯ２对可见光（波长在５１５ｎｍ）的吸收系数分别为１．２ｃｍ２／Ｊ和６×１０－２ｃｍ２／Ｊ，ＳＯ２的寿命为３８ｓ。最后本文给出了采用这种ＳＯ／ＰＶＡ膜实现紫外－可见光图像转换和空间光调制操作的实验演示结果     

光泵腔式NH3分子远红外激光的最佳工作气压研究

通过求解量子系统的密度矩阵方程，采用迭代法计算了光泵腔式ＮＨ３分子远红外激光的输出功率密度。在此基础上，对光泵腔式远红外激光的工作气压进行了理论研究。结果表明最佳工作气压与腔的功率反射系数、样品管的长度以及泵功率密度等工作参数之间是相互制约的，同时与参与激光过程的能级有关。在实验上采用电感性金属栅网作为反射器，设计制作出长度分别为１００ｃｍ、２０ｃｍ和１０ｃｍ的Ｆａｂｒｙ－Ｐｅｒｏｔ腔式远红外激光器，然后和ＴＥＡ－ＣＯ２激光器作泵浦源，成功地获得光泵ＮＨ３分子远红外激光，测量结果表明理论计算与实验数据相符。     

Ge_xSi_（1－x）／Si异质结无间距定向耦合光开关模型分析

提出一种简便可行的ＧｅｘＳｉ１－ｘ异质结无间距定向耦合光开关（ＢＯＡ型－ＢｉｆｕｒｃａｔｉｏｎＯｐｔｉｃａｌＡｃｔｉｖｅ）模型分析方法。该方法采用等离子体包散效应分析了这种光开关的电学调制机理；采用异质结超注原理分析了开关的电学性质；并根据典单模脊形波导理论和上述分析，设计了利用双模干涉机制工作的Ｇｅ０．０５ＳＩ０．９５／Ｓｉ异质结ＢＯＡ型光开关的结构参数和电学参数。     

TlBaCaCuO外延膜的光响应

在波长γ＝６３２．８ｎｍ，入射功率约０．８ｍ的Ｈｅ－Ｎｅ激光照射下，对ＴｌＢａ２Ｃａ２ＣｕＯ２（Ｔｌ－２２１２）外延膜的光响应行为进行了实验研究。结果显示：在样品转变温度（Ｔｃ＝１０５．５Ｋ）附近，ＴｌＢａ－ＣａＣｕＯ外延膜的光响应行为表现为辐射热与非辐射热效应共存现象。光响应信号电平与样品温度、偏置电流、及入射光束的调制频率等诸因素有密切关系的关系。实验结果还表明，辐射热与非辐射热效应的响应行为     

Optical Activity of Benzil Crystal

Optical activity of benzil as an example of optically active matter in the crystalline state only, not in solution, is studied for the wavelengths ranging from 0.320 m to 0.585 m. Previously measured experimental data are approximated by the theoretical set of formulas, which were derived by the use of the three coupled oscillators model. The earlier published formula consisting of six terms differed from the experimental data particularly in the wavelength region (0.380-0.510) m. This formula is replaced by the twelve-term formula which was computed by our specially worked computer program for the interpretation of the experimental data of optical activity based on the Marquardt-Levenberg method of the sum of least squares minimization. The possibility of molecular contribution to the resulting optical activity of benzil is mentioned. The use of Kramers-Kronig transforms for the determination of the circular dichroism curve based on the optical rotatory dispersion result is shown. The theoretically computed circular dichroism is compared with the available experimental data.     

A planar chiral nanostructure with asymmetric transmission of linearly polarized wave and huge optical activity in near-infrared band

Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The designed nanostructure that consists of twisted metallic split-ring resonators on both sides of a dielectric substrate achieves asymmetric transmission for a forward and backward propagating linearly polarized wave by numerical simulation in near-infrared band. Difference in transmission efficiency of the optimized structure between the same polarized waves incident from opposite directions can reach a maximum at the communication wavelength （1.55 μm）. Moreover, the simulation results of this structure also exhibit strong optical activity and circular dichroism.     

木榄醇手性光谱的密度泛函研究

手性光学理论研究有助于解释手性分子的旋光机理和设计新的手性药物.采用B3LYP方法,计算了木榄醇A—C的旋光度和圆二色谱.从分子结构、正则振动和电子结构方面,探索了分子手性微观起源,分析了旋光度和电子圆二色谱的溶剂效应.表明OH的引入可调节分子的手性,甲基和苯环加强了分子的手性.发生在手性骨架上的振动和电子跃迁,加强了分子的手性.溶剂效应减小旋光度、削弱电子圆二色谱. 关键词： 木榄醇 光学活性 密度泛函理论 圆二色谱     

圆二色性对旋光现象的影响

分析旋光活性物质的圆二色性对旋光现象的影响,给出了一种测量介质圆二色性的方法。     

Chiralvs. symmetric states in optical isomers

Summary An extension of a recent model explaining the stability of chiral molecules is presented here. From the comparison between the energy reduction produced by the adoption of a chiral form and that produced by a symmetric superposition of chiral states it is concluded that the true fundamental state of the chiral molecules is the chiral one, which eliminates the well-known ?optical-isomers paradox?. Also, a discussion on the main differences between the approach used here and the previous attempts of explanation based in the double-well model is made. The authors of this paper have agreed to not receive the proofs for correction.     

On gyrotropic chiral sculptured thin films for magneto-optics

The planewave response of a chiral sculptured thin film with gyrotropic properties is examined, under the assumption of axial excitation. Although the reflectances and the transmittances are definitely affected by gyrotropy, the circular Bragg phenomenon is still exhibited. Most importantly, structural chirality and gyrotropy contribute cooperatively to transmission optical rotation.     

Racemization produced by elastic molecular collisions in dilute gases

Summary A two-level approach is developed to explain the racemization in dilute gases produced both by natural tunnelling and by elastic molecular collisions.     

Effect of Environmental Cations on Force Constants,Vibrational Mean Amplitudes and Bond Order of Metaloxygen Bonds in Some Octahedral Oxyanions

The general valenoe force field (GVFF), modified orbital valence force field (MOVFF), and modified Urey-Bradley force field (MUBFF) have been employed to calculate the force constants of octahedral Te⁶⁺o₆, and Ti⁴⁺o₆ anions in the presence of different environmental cations. The mean amplitudes and generalized mean square amplitudes of vibrations for these anions at temperatures; O°K,298. 16°K, and 500°K have also been calculated. Further, the metaloxygen bond order was estimated with the help of general valence stretching force constants. The effects of environmental cations on the force constants, mean amplitudes and π-bonding of metal-oxygen bonds have been critically discussed. The effect of atomic masses of anions on the ooriolis coupling constants of ‘f_iu species has also been outlined.     

Density functional study on chirospectra of hydrogen-bonded systems X-（H2O）3（X=F,Cl,Br,I）

This paper calculates the molecular structures,infrared,Raman,circular dichroism spectra and optical rotatory powers of some hydrogen-bonded supramolecular systems as a cyclic water trimer,(H2O)3 and its pyramidal halide complexes,X-(H2O)3(X = F,Cl,Br,I) with the gradient-corrected density functional theory method at the B3LYP/6-311++G(2d,2p) and B3LYP/Aug-cc-pVTZ levels.It finds that the complexation of halide anions with the water trimer can efficiently modulate the chirally optical behaviors.The calculated vibrational circular dichroism spectrum illuminates that the vibrational rotational strength of S(+)-(H2O)3 mostly originates from the O-H rocking modes,whereas chirality of S(-)-X-(H2O)3(X = F,Cl,Br,I) has its important origin in the O-H stretching modes.The calculated optical rotatory power demonstrates that S(+)-(H2O)3 and S(+)-F(H2O)3 are positively chiral,whereas S(-)-X-(H2O)3(X = Cl,Br,I) are negatively chiral.With the polarizable continuum model,calculated bulk solvent effect in the solvents water and carbontetrachloride and argon shows that the positive chirality of S(+)-(H2O)3 is enhanced and the negative chirality of S(-)-X-(H2O)3(X = Cl,Br,I) and the positive chirality of S(+)-F(H2O)3 are reduced with an augmentation of the solvent dielectric constant.     

Incident circularly polarized Raman optical activity spectrometer based on circularity conversion method

A simple incident circular polarization Raman optical activity (ICP ROA) spectrometer was constructed by applying the method of circularity conversion. The circular polarization of the incident laser light was modulated between right and left by the insertion of a half‐wave plate and not by using a Pockels cell which is usually used in ICP ROA instruments. On the basis of the concept of the virtual enantiomer (Hug, W. Applied Spectroscopy, 2003, 57, 1), circularity converters were inserted in the optical train, which could effectively compensate the systematic offset. The new instrument successfully attained photon shot‐noise‐limited conditions for all bands except for the very strongly polarized Raman band. The ROA spectra of some standard chiral samples were measured to demonstrate the performance of the spectrometer. Copyright © 2010 John Wiley & Sons, Ltd.