磁场中HD分子振转跃迁的超精细结构

HD分子红外跃迁的精密测量被用以检验量子电动力学、确定质子-电子质量比等.但HD分子的超精细结构分裂对于测量精度是一个很重要的限制因素,并可能是实验中测得n=2—0谱带跃迁呈特殊线型的原因之一.本文分别在耦合表象和非耦合表象下计算了HD分子振转跃迁的超精细结构,并计算了不同外加磁场下HD分子(2–0)带中R(0), P(1), R(1)线的超精细结构,模拟了10 K低温下对应的光谱结构.结果表明, HD分子跃迁结构可随磁场发生明显变化.这可能有助于分析HD分子跃迁特异线型产生的机制,进一步获得其准确的跃迁中心频率,用于基础物理学检验.     

偏振三光子跃迁讯号的理论计算

本文从密度矩阵运动方程出发, 对四能级阶跃型及折迭型能级结构的分子系纬与不同性质偏振激光场作用时, 可能发生的五种近共振增强三光子电子跃迁分别作了具体推导, 获得了以第三跃迁为探测跃迁时的实验讯号强度及光谱特征解析式. 通过与三能级系统作比较, 发现其线型因子、谱线强度因子均有不同程度的增大, 使讯号相对强度有数量级的提高. 最后还讨论了所得讯号在分子光谱分析中的应用前景. 关键词：     

偏振三光子跃迁讯号的理论计算

本文从密度矩阵运动方程出发,对四能级阶跃型及折迭型能级结构的分子系综与不同性质偏振激光场作用时,可能发生的五种近共振增强三光子电子跃迁分别作了具体推导,获得了以第三跃迁为探测跃迁时的实验讯号强度及光谱特征解析式。通过与三能级系统作比较,发现其线型因子、谱线强度因子均有不同程度的增大,使讯号相对强度有数量级的提高。最后还讨论了所得讯号在分子光谱分析中的应用前景。 关键词：     

高组分稀磁半导体Cd1-xMnxTe/CdTe超晶格的荧光谱研究

报道用分子束外延(MBE)技术生长的x=0.4,0.8的高组分稀磁半导体Cd1-xMnxTe/CdTe超晶格低温和室温荧光谱研究结果.基态激子跃迁能级荧光谱实验结果显示高组分超晶格中具有高量子效率和高质量光发射.对激子能级随温度的变化进行了详细研究,给出激子跃迁能量的温度系数.激子能级线型的展宽随温度变化关系可用激子-纵向光学声子耦合模型解释.与光调制反射谱实验结果进行了比较.     

电场调制激光光谱对NO2分子激发态电偶极矩的测定

本文采用Ｓｔａｒｋ调制光谱对ＮＯ２分子５９３ｎｍ附近的Ａ×２Ｂ２←Ｘ＾２Ａ１跃迁进行了测量，通过强度分析得到＾２Ｂ２激发态的电偶极矩常数。对简并态能级则通过线型分析拟合出委态的电偶极矩。     

单分子瞬时带电态中电子-振动耦合特性的亚纳米荧光成像研究

分子内的电子-振动耦合特性对电子跃迁和分子光谱特征有重要影响,是分子光谱学研究的中心课题之一.本文利用具有亚纳米分辨的扫描隧道显微镜诱导发光成像技术,通过高度局域的隧穿电子来充电激发单个苝四甲酸二酐分子,研究该分子的瞬时带电态(–2价态)的电致发光特性以及相应的电子-振动跃迁的实空间成像特征.具有亚分子分辨的光谱成像结果表明, 0-0纯电子跃迁的光子图“两点”亮斑特征是沿分子短轴的,而某些电子振动峰的光子图“两点”亮斑方向却沿着分子长轴,相对于0-0跃迁光子图的图案旋转了90°.这表明这些振动态所对应的跃迁偶极取向是沿着分子长轴的,相对于0-0的纯电子跃迁的偶极取向发生了明显的变化,说明这些分子振动模式在电子的跃迁过程中对电子态空间分布产生了重要扰动.理论计算表明,这种跃迁偶极的变化源自于与Herzberg-Teller贡献相关的电子-振动耦合.反对称的振动模式对纯电子跃迁的跃迁密度、特别是具有较大跃迁密度的原子产生了强烈的动态扰动,或者说对分子波函数进行了“整形手术”,从而诱导出沿分子长轴方向的跃迁电荷振荡,引发沿分子长轴的跃迁偶极.本文结果为从实空间的视角来直观理解分子瞬时带电态中...     

对称陀螺分子PH30010-0000跃迁带的高温线强度计算

通过直接计算分子配分函数并将常温下的无转动跃迁偶极矩平方近似为一常数应用到高温,计算了对称陀螺分子PH3 0010-0000跃迁的高温线强度。在296K,计算的分子总配分函数与HITRAN数据库的结果符合很好,只有-0.075%的百分误差。计算的跃迁线强度在2000 K和3000 K的高温与HITRAN数据库的结果也吻合较好,表明分子配分函数和线强度的高温计算是可靠的。在此基础上,进一步计算了更高温度4000和5000 K的跃迁线强度,报道了对称陀螺分子PH3 0010-0000跃迁在极端高温4000和5000 K的模拟光谱。计算结果对大气分子高温光谱的实验测量和理论研究均有一定的参考价值。     

偏振调制双光子光谱理论计算

本文从密度矩阵运动方程出发,推导出当各种不同偏振调制激光场与三能级粒子系统相互作用时,同核双原子分(具近共振中间能波)单重电子态之间的双光子跃迁所产生的荧光信号强度和线型.对比偏振调制的与光子强调制的信号强度和线型时,表明:偏振调制双光子光谱(PMTPS)不仅能消除由吸收同一光束的同向双光子所产生的多普勒加宽背景,极大地提高光谱分辨率;而且不同电子态之间跃迁的O、P、Q、R、S支谱线强度与激光偏振状态有关,可借以标识分子的高激发电子终态和转动能级,有选择地简化复杂的分子光谱.可以预期,PMTPS是研究分子光谱和高分辨率激光光谱极有用的一种技术.     

对称陀螺分子PH30010-0000跃迁带的高温线强度计算

通过直接计算分子配分函数并将常温下的无转动跃迁偶极矩平方近似为一常数应用到高温，计算了对称陀螺分子PH3 0010-0000跃迁的高温线强度。在296K，计算的分子总配分函数与HITRAN数据库的结果符合很好，只有-0.075%的百分误差。计算的跃迁线强度在2000 K和3000 K的高温与HITRAN数据库的结果也吻合较好，表明分子配分函数和线强度的高温计算是可靠的。在此基础上，进一步计算了更高温度4000和5000 K的跃迁线强度，报道了对称陀螺分子PH3 0010-0000跃迁在极端高温4000和5000 K的模拟光谱。计算结果对大气分子高温光谱的实验测量和理论研究均有一定的参考价值。     

前途广阔的“准分子”激光器

一、引 言 通常的分子气体激光器,在激光跃迁的过程中分子不发生分解现象,就是说进行跃迁的上、下能级都对应着分子的“稳定状态”.举例来说,我们熟知的二氧化碳激光器和氮分子激光器就是属于此种类型,在激光跃迁过程中,分子不产生任何分解——组成分子的几个原子始终紧密地“束缚”在一起.这种类型的跃迁叫作“束缚态-束缚态”跃迁,意指其上、下能级部对应着分子的“束缚”状态. 近年来获得迅速发展的“准分子”激光器1)不同于上述基于“束缚态-束缚态”跃迁的通常激光器.它们的跃迁属于“束缚态-自由态”的类型,就是说,“准分子”在上能级…     

Soliton molecule in fiber laser

The soliton molecule is achieved in nonlinear polarization rotation fiber laser. The structure of soliton molecule is heterogeneous diatomic molecule. The soliton molecule originates from the splitting of the high energy soliton. The dips of the soliton molecule spectra show that there is the interaction between the constituents of the soliton molecule, resulting in that the constituents are in the bound state as a unit. The laser bias can change the fine structure of the soliton molecule, which can be observed in the autocorrelator and oscilloscope.     

Fabrication and electrochemistry study of multi-thiol coronary molecule monolayers

Single-component monolayer of novel multi-thiol coronary molecule and two-component mixed monolayer composed of coronary molecule and n-alkanethiol on gold substrates are described. The assembly of monolayers is characterized by ellipsometry, infrared spectroscopy and X-ray photoelectron spectroscope. The electrochemical properties of the single- and two-component monolayers are evaluated by cyclic voltammetry and electrochemical impedance spectroscopy experiments. Coronary molecule with multi-thiol groups has the ability to form stable monolayer via the interaction of mercapto groups and Au surface. Electrochemical impedance measurements indicate that 89.9% of the gold surface is blocked by the coronary molecule, which is attributed to the special spatial structure of the coronary molecule. The uncovered site on gold surface in coronary molecule monolayer could be occupied by the second suitable molecule. The mixed monolayer prepared by stepwise assembly of coronary molecule and n-alkanethiol has complete compact packing and few defects.     

光诱导雄黄矿物同质异象变化的显微成像拉曼散射研究

利用拉曼光谱研究了激光照射诱导雄黄的同质异象变化,这些结果证实了下面的反应：由于As—As键相对较弱,首先As—As键被破坏,有1个S原子加入到As—As键中,形成As—S—As键。此时由As₄S₄(Realgar类型)变化为As₄S₅相,而As₄S₅处于不稳定状态,As₄S₅相变化为 Pararealgar时有1个S原子从As—S—As键中释放出来。释放出来的S原子又加入到另外1个As₄S₄(Realgar)中,引起As₄S₄(Realgar)相变化为As₄S₅,As₄S₅进而分裂为1个S原子和As₄S₄(Pararealgar类型)。照射促进雄黄经由 As₄S₅ 分子被转换成副雄黄。     

Gas-sensor property of single-molecule device:F_2 adsorbing effect

The single thiolated arylethynylene molecule with 9,10-dihydroanthracene core(denoted as TADHA) possesses pronounced negative differential conductance(NDC) behavior at lower bias regime. The adsorption effects of F_2 molecule on the current and NDC behavior of TADHA molecular junctions are studied by applying non-equilibrium Green's formalism combined with density functional theory. The numerical results show that the F_2 molecule adsorbed on the benzene ring of TADHA molecule near the electrode can dramatically suppresses the current of TADHA molecular junction. When the F_2 molecule adsorbed on the conjugated segment of 9,10-dihydroanthracene core of TADHA molecule, an obviously asymmetric effect on the current curves induces the molecular system showing apparent rectifier behavior. However, the current especially the NDC behavior have been significantly enlarged when F_2 addition reacted with triple bond of TADHA molecule.     

Theoretical Exploration of the Isotopic Effect on Molecular High-Order Harmonic Generation

The isotopic effect on the generation of the molecular high-order harmonics is studied by numerically solving the one-dimensional time-dependent Schrödinger equation when the model hydrogen molecule ions/hydrogen deuterium molecule ions are exposed to an intense laser pulse. To explain the effect more clearly, not only the ionization probabilities but also the electron–nuclear probability density distributions and time-frequency profiles are calculated. The results show that more intense harmonics are generated in the asymmetric diatomic molecule ions/hydrogen deuterium molecule ions than those of hydrogen molecule ions. Moreover, the interference minimum in the harmonic spectra is investigated by adjusting the laser intensity and the initial vibrational state. It is shown that the interference minimum is sensitive to the laser intensity and the initial vibrational level for hydrogen molecule ions; in contrast, it is only dependent on the initial vibrational level for hydrogen deuterium molecule ions.     

电场作用下C60富勒烯二聚体分子的几何构型与失效

采用分子力学与量子力学相结合的方法,模拟了电场作用下C60富勒烯二聚体(2C60)分子的几何构型与失效行为,讨论了三种不同方向外加电场对2C60分子几何变形、构型失效、电荷分布与极化偶极矩的影响,并与电场作用下C60富勒烯分子的几何变形与失效行为进行了对比.研究结果表明,2C60分子的几何变形与失效行为与外加电场的方向密切相关.当外加电场与2C60分子的桥接C-C键平行时,2C60分子很容易发生失效,且失效形式也十分独特.     

表面活性荧光探针分子与牛血清蛋白的相互作用

研究了两种表面活性荧光探针分子2-(对-十二烷基氨基)苯基-3,3-二甲基-5-乙酯基-3H-吲哚基-甲基-二-十六烷基碘化铵(1)和2-(对-十二烷基氨基)苯基-3,3-二甲基-5-乙酯基-3H-吲哚基-二甲基-十八烷基碘化铵(2)与牛血清蛋白(BSA)之间的相互作用。根据结合反应的温度效应求得热力学函数并推断探针分子与BSA结合的作用力类型;分子1和2与牛血清蛋白之间存在能量转移现象,根据Frster非辐射能量转移理论计算得到给体-受体之间的距离分别为2.90和4.02 nm。     

Fiber-mesh photonic molecule

Analogous to the photonic crystal, we introduce the concept of a fiber-mesh photonic molecule made up of optical fibers and study its transmission characteristics. We consider a specific example of a photonic molecule, inspired by the well-known C₆₀ molecule, with the arms of the molecule formed out of single-moded optical fibers. The transmittance consists of sharp peaks determined by the pole structure of the scattering matrix in the complex energy plane. A molecule can be designed to control the positions and the widths of the transmission peaks, opening up the possibility of building new photonic devices such as high quality band-pass filters.     

A density functional theory study on the adsorption of CO and O₂ on Cu-terminated Cu₂O（111） surface

The adsorptions of CO and O2 molecules individually on the stoichiometric Cu-terminated Cu2O(111) surface are investigated by first-principles calculations on the basis of the density functional theory.The calculated results indicate that the CO molecule preferably coordinates to the Cu2 site through its C atom with an adsorption energy of -1.69 eV,whereas the O2 molecule is most stably adsorbed in a tilt type with one O atom coordinating to the Cu2 site and the other O atom coordinating to the Cu1 site,and has an adsorption energy of -1.97 eV.From the analysis of density of states,it is observed that Cu 3d transfers electrons to 2π orbital of the CO molecule and the highest occupied 5σ orbital of the CO molecule transfers electrons to the substrate.The sharp band of Cu 4s is delocalized when compared to that before the CO molecule adsorption,and overlaps substantially with bands of the adsorbed CO molecule.There is a broadening of the 2π orbital of the O2 molecule because of its overlapping with the Cu 3d orbital,indicating that strong 3d-2π interactions are involved in the chemisorption of the O2 molecule on the surface.     

纳米银粒子表面吸附染料分子的荧光增强及荧光猝灭现象

本文通过阴、阳离子型染料分子荧光素钠(FS)及若丹明6G(Rh6G)吸附在银胶体系内纳米银颗粒表面上,首次发现了FS的荧光增强谱及Rh6G的荧光猝灭谱.引起荧光增强及荧光猝灭的因素,除局域场和分子到金属表面能量转移这两个方面外,还与纳米银表面与被吸附分子之间的距离有关.