Autler--Townes doublet in novel sub-Doppler spectra with caesium vapour cell

With a coupling laser locked to caesium 6S$_{1 / 2}$ $F_{\rm g}$=4--6P$_{3 / 2}$ $F_{\rm e}$=5 cycling transition and a co-propagating probe laser scanned across 6S$_{1 / 2}$ $F_{\rm g}$=4--6P$_{3 / 2}$ $F_{\rm e}$=3, 4 and 5 transitions, a novel scheme for sub-Doppler spectra in Doppler-broadened V-type three-level system is demonstrated by detecting the transmission of the coupling laser through a caesium vapour cell. The Autler--Townes doublet in the sub-Doppler spectra of the coupling laser is clearly observed. The effects of coupling laser intensity on the splitting and linewidth of the Autler--Townes doublet are experimentally investigated and the results agree well with theoretical predictions. Taking the multiple hyperfine levels of caesium atom into account, a brief analysis is presented.     

Coalescence coupled with either coagulation or flocculation in dilute emulsions

In current theories [R.G.P. Borwankar, L.A. Lobo, D.T.G. Wasan, Colloids Surf. 69 (1992) 35; K.D. Danov, N.D. Denkov, D.N. Petsev, R. Borwankar, Langmuir 9 (1993) 1731; S.S. Dukhin, J. Sjöblom, J. Dispers. Sci. Technol. 19 (1998) 311], emulsion destabilization is considered as the combined processes of droplet coagulation/flocculation and coalescence. Irreversible aggregation is usually called coagulation, and the term flocculation is used for reversible aggregation. These theories have different conditions of applicability which are not specified. An approximate criterion for discrimination between coalescence coupled with either coagulation or flocculation in dilute emulsions is proposed. Such discrimination is made possible by comparing the characteristic time for coagulation (Smoluchowski time) with that for floc fragmentation (droplet doublet lifetime, τ_d). As droplet dimension and electrolyte concentration decrease, and the Stern potential increases, τ_d is reduced and flocculation takes place. The quantity τ_d enables one to specify the conditions for the two separate cases. The important role of retarded van der Waals forces, screening length and hydration forces in emulsion coalescence is demonstrated.     

铷蒸气Λ-型系统中的受激Raman谱与光泵效应

从理论和实验上研究了⁸⁵Rb 原子蒸气D1线系统中的受激Raman现象. 在Λ-型能级系统中, 抽运光对弱探测光的影响有两部分: 受激Raman激发和光泵效应. 在一定的抽运光强度和失谐量条件下, 受激Raman谱表现为增益谱或损耗谱; 以光泵效应导致的吸收谱为背景时, 便分别形成了窄线宽透明窗口或线宽差异很大的吸收双线. 理论模拟和实验结果基本符合. 基于这些研究, 从新的角度阐述了在Λ-型系统中的电磁感应透明和Autler-Townes分裂这两个重要现象与受激Raman谱之间的关系. 关键词： 受激Raman谱 光泵效应 电磁感应透明 吸收双线     

TC模型中PGB对Tevatron上tt产生截面的单圈修正

分别在一代TC模型(OGTC)和最近由Georgi等人提出的带有一个无质量的标量子的TC模型(MTC)中计算了赝标哥尔斯通粒子(PGB)对Tevatron上qqtt过程的单圈修正. 发现在OGTC和大部分的参数空间中,PGB的修正是减小tt对截面的,如果色八重态PGB的质量可以取到150GeV的话,该修正达到-38%,这样的修正值是有实验意义的.     

A Pure-Red Doublet Emission with 90 % Quantum Yield: Stable,Colorless, Iodinated Triphenylmethane Solid

Red luminescence is found in off-white tris(iodoperchlorophenyl)methane ( 3I-PTM^H ) crystals which is characterized by a high photoluminescence quantum yield (PLQY 91 %) and color purity (CIE coordinates 0.66, 0.34). The emission originates from the doublet excited state of the neutral radical 3I-PTM^R , which is spontaneously formed and becomes embedded in the 3I-PTM^H matrix. The radical defect can also be deliberately introduced into 3I-PTM^H crystals which maintain a high PLQY with up to 4 % radical concentration. The immobilized iodinated radical demonstrates excellent photostability (estimated half-life >1 year under continuous irradiation) and intriguing luminescent lifetime (69 ns). TD-DFT calculations demonstrate that electron-donating iodine atoms accelerate the radiative transition while the rigid halogen-bonded matrix suppresses the nonradiative decay.     

FRAGMENTATION OF PRIMARY FLOCS IN EMULSIONS AND THE SUBSEQUENT REDUCTION OF COALESCENCE

In existing theories emulsion desiabilization is considered as the combined processes of irreversible flocculation and coalescence of dispersed droplets. This approach can be justified when the potential pit characterizing the energy of droplet interaction is sufficiently deep, i.e. excluding small droplet dimensions, strong electrosiatic repulsion and low electrolyte concentrations. For smaller droplet dimensions and stronger electrostatic repulsions the emulsion instability must be considered as a combined process of reversible flocculation and coalescence. In this paper a mathematical model that couples the kinetics of flocculation, coalescence and floe fragmentation is developed in order to quantify the kinetic instability of emulsions with charged submicron droplets. The characteristic limes for flocculation (Smoluchowski's time τ_c) for coalescence (coalescence time τ_c) and for disaggregation (doublet lifetimeτ_d) are considered model parameters. The mathematical model applies to the case when and τ_d<< τ_c, which corresponds to a situation with a small multiplet concentration compared to the concentration of doublets and a singlet-doublet quasi-equilibrium. It is established that at singlet-doublet quasi-equilibrium the rate of the decline in the total droplet concentration is described by second order kinetics in distinction to the exponential time dependence valid for coalescence at irreversible flocculation. The double disintegration reduces the entire coalescence rate, expressed as τ_sm/ τ_d. This reduction is very large at small values of Td. The mathematical model presented can hased on the spontaneous disintegration of doublets predict changes in emulsion stability for model systems and also for technologically important emulsions.     

基于非对称粒子空穴组态的手征双重带

利用三轴形变的粒子转子模型对基于非对称粒子空穴组态πg–1 9/2 νh11/2和πh–1 11/2 νi13/2等的手征双重带进行了研究.详细分析了转动能谱、角动量随转动频率的变化关系、以及约化跃迁几率B(E2)和B(M1)等性质.发现基于非对称组态的三轴形变原子核也有类似对称组态的手征双重带现象.但它们所对应的最佳三轴形变值从γ=30°变为γ～27°.随着组态中价核子角动量的增加,出现手征双重带的自旋随之增加,简并区间也相应增大     

Description of Chiral Doublet Bands in Odd-Odd Cs Isotopes

Properties of the chair doublet bands of the odd-odd Cs isotopes built on the πh11/2× vh11/2 configuration are investigated systematically within the supersymmetry scheme including many-body interactions and possessing the SO（5）（or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the energy spectra, the energy staggering parameter as a function of the spin are obtained. The calculation shows that the stronger competition between the pairing and anti-pairing effects and the SU（3） symmetry broking more seriously exist in the stable chiral structure.     

Study of Radiative Decays Ds1（2536） → Ds（1968） ＋γ and Ds1（2536）→ Ds^＊（2112） ＋ γ in CQM Model

There are some uncertain charazteristics of the Ds1（2536）, which deserves further discussion. Based on the assumption that the meson is constituted by c s, and belongs to T doublet （1^＋, 2^＋）, radiative decays Ds1（2536） → Ds（1968） ＋γ and Ds1（2536） → Ds^＊（2112） ＋ γ are studied in the CQM model The large branching ratios of them from our calculations not only indicate the process may be detected in the future experiments, but also can give a deep comprehension of the structure of it.