Autler-Townes splitting in photoelectron spectra of K2 molecule

We investigate Autler-Townes splitting in the photoelectron spectra of K₂ molecule driven by pump-probe pulses via employing the time-dependent wave packet approach.It is found that the magnitude of Aulter-Townes splitting varies with the wavelength of the intense laser pulse.In particular,the phenomenon of Aulter-Townes splitting vanishes for the far-off resonance of the pump pulse.Also,the split peaks of Autler-Townes in the case of resonant pump pulse give us an approach to directly obtaining the transition dipole moment of a molecule.     

Mg、Na原子的嵌入对富勒烯C50的电子传输特性与负微分电阻效应的影响简

采用基于密度泛涵理论的第一性原理和非平衡格林函数方法研究了Mg、Na原子的嵌入对于C50 分子的电子传输特性与负微分电阻效应的影响．结果显示Mg、Na原子的嵌入明显改变了C50分子的负微分电阻效应,且大大增强了C50分子的电子传输性能．     

用代数-能量自洽法研究双原子分子解析势能函数

基于计算双原子分子完全振动能谱及离解能的代数方法 (algebraic method,AM)和研究双原子分子解析势能函数的能量自洽法(energy consistent method,ECM),建立了计算双核分子体系精确解析势能函数的代数-能量自洽法(AM-ECM).应用AM-ECM方法研究了7Li+2-23Σg,KH-X1Σ+,NaLi-X1Σ+和NaLi-A1Σ+电子态的解析势能表达形式,并与其他方法的研究结果进行了比较,获得了能正确描述这些电子态在渐近区和离解区的精确解析表达结果.     

氧分子离子A2∏u-X2∏g态转动光谱分析

利用光外差-速度调制吸收光谱技术,测量了氧气分子离子在11385～12100 cm^-1的多普勒分辨吸收光谱,获得的谱线被指认到该分子离子第二负带的(2,19)、(3,20)、(5,21)跃迁谱带．利用全局拟合方式,得到了涉及能级的精确分子常数．     

静电场诱导的分子双光子吸收截面和光限幅性能的变化

采用时域有限差分法数值求解麦克斯韦-布洛赫方程,研究了当存在静电场时少周期脉冲激光在4,4'-二(二正丁胺基)二苯乙烯(BDBAS)分子介质中的传播过程,得到了分子的动态双光子吸收(TPA)截面并且展示了其光限幅行为. 由于静电场的存在打破了BDBAS分子的对称性,因此激光在传播过程中,其频谱同时出现了偶次谐波和奇次谐波. 随着静电场强度的增加,分子的动态TPA截面增大,同时光限幅效应更为明显.     

Electron Transfer in Metal‐Organic Molecules. A Time Resolved EXAFS and Optical Spectroscopy Study

We have measured, by means of ultrafast x‐ray absorption and optical spectroscopy, the M‐O (M=Fe, Co) and Co‐N metal to ligand bond length change as a function of time and the formation and decay of the excited states and intermediate species, after excitation with a 267 nm femtosecond pulse. These experimental data combined with DFT calculations allowed us to determine the mechanism of electron transfer operating in the redox reaction of two metal‐ligand complexes, [M(III)(C₂O₄)₃]^3‐ and [Co(III)(NH₃)₆ ]³⁺. Based on the data we find that, even though both molecules are excited into their charge transfer band, the redox reaction of [M(III)(C₂O₄)₃]^3‐ proceeds via intermolecular electron transfer while [Co(III)(NH₃)₆ ]³⁺ electron transfer mechanism is intramolecular.     

Synthesis and Surface Activity of Anionic Gemini Surfactants with Alkyl Spacers

A series of anionic Gemini surfactants called alkanediyl-α,ω-bis(m-octylphenoxy sulfonate) with different length of (CH₂)_x spacer, C₈C_xC₈ (x = 2, 4, 6, 8), have been synthesized from 4-n-octylphenol and their basic physicochemical properties are investigated. The results indicate that they are different from cationic Gemini surfactants called alkanediyl-α,ω-bis(dimethyldodecylammonium bromide), 12-(CH₂)_s-12, in the literature. It is found that as the carbon atom number of the spacer increases, the cmc (critical micelle concentration) decreases gradually, and the surface area per molecule (A_min) decreases initially and then increases. The breakpoints appear at number 4 of carbon atom in the spacer. Though the length of the spacer is different for the Gemini surfactants from C₈C₂C₈ to C₈C₆C₈, there is no obvious change on the micropolarity.     

Odd–even effect in biphenyl‐based symmetrical dimers with methylene spacer – evidence of the B4 phase

A series of 4‐decyloxy‐4′‐hydroxybiphenyl esters of α,ω‐alkanedicarboxylic acids containing two mesogenic units connected by a methylene spacer was synthesized. The mesogenic properties of the compounds were investigated by polarising optical microscopy, differential scanning calorimetry and X‐ray diffraction methods. A strong influence of the spacer length and its parity on the mesomorphic properties was found. A dramatic odd–even effect was observed for the clearing temperatures and entropies. Compounds with an even number of carbon atoms in the methylene spacer formed tilted smectic phases, whereas compounds with an odd number of carbon atoms in the spacer exhibited the B4 phase, characteristic of bent‐shaped molecules.     

ADDITIONS DES FONCTIONS SUR LA DOUBLE LIAISON DES VINYL SPIROPHOSPHORANES SYNTHÈSE DES α ET β AMINO SPIROPHOSPHORANES ALCOOLYSE DE LA LIAISON P—C DANS LES COMPOSÉS D'ADDITION OBTENUS

Abstract

Addition of amines and of hydrogenphosphonates on the carbon-carbon double bond belonging to vinyl-phosphoranes is examined. The stereochemistry and reactivity of the saturated adducts obtained is rationalized. Alcoholis of the P—C bond is also studied.     

Organic Fluorescent Molecule with High Solid State Lumines- cent Efficiency and Protonation Stimuli-response

A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis（2,2-di（pyridin-2-yl）- vinyl）benzene （BDP2VB） was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission （AIE） property. According to the crystal struc- ture analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.