A compact formula for the coupling efficiency associated with mirrors in waveguide lasers

This paper presents a simple theory based on the diffraction integral approach for calculating the coupling efficiency in waveguide lasers which employ plane or spherical mirrors. The results obtained differ only slightly from a full rigorous approach, due to the fact that only less than one percent of the beam energy lies outside the waveguide aperture. The infinite aperture approximation employed here leads to an explicit compact formula for the coupling efficiency, whereas exact calculations lead to expressions requiring numerical integration for their evaluation.     

Study of a carbon dioxide ring laser gyroscope

We have experimentally investigated a basic ring laser gyroscope (RLG) with carbon dioxide gain, and studied the prospects of developing a practical CO₂ RLG. Rotation sensing was demonstrated on a number of transitions in the 9.4 m and 10.4 m vibration-rotation bands. Gyro response is discussed with regard to lock-in, bias, homogeneous broadening effects, and high power operation. We show that such a system may offer important advantages over standard helium-neon RLGs, including reduced quantum limit and backscattering. The prospects and possible approaches for developing a practical high power CO₂ RLG are discussed, and a method of eliminating cross-saturation at high pressure is proposed and analyzed.     

New measurements and analysis of the far-infrared spectrum of CH2DOH in the lowest torsional vibrational state (e0)

In this work the far infrared (FIR) absorption spectrum has been measured for the asymmetrically mono deuterated Methanol (CH₂DOH) species in the wavenumber range of 15–1200 cm⁻¹ better accuracy and signal/noise ratio than known before. Assignments have been made for b-type transitions in the lowest lying torsional vibrational state trans-(e₀) for a wide range of rotational angular momentum. The assignments have been rigorously confirmed by the residual loop defect methods. The ^rR–branch wavenumbers are analyzed by the usual state dependent expansion parameters and the Q-Branch origins. These origins have been used to calculate the torsional and torsional-rotation interaction contributions. These findings are in good agreement with predicted from the Hamiltonian model described in recent publications. A large number of assignments have also been made in the millimeter wave spectrum recorded earlier and thereby evaluated the asymmetry splitting parameters for 4 different axial rotational angular momentum quantum numbers. The analysis and interpretation of the spectra are reported. New assignments for about 260 transitions are included the text and a catalog of about 1500 transitions belonging to the e₀ species is prepared (Appendix 1) and is made available through the open server in “Research Gate” and will be freely available to others.     

On the Reactivity of Metal and Organometallic Halides and Pseudohalides Towards Stannosiloxane (Ph3Sn-O-SiPh3)

Abstract

Interactions of HgX₂ (X = Cl, Br, I, SCN, CN, NCO), SbCl₃, TeCl₄, and PhTeCl₃ with Ph₃Sn-O-SiPh₃ at room temperature have been found to proceed with the simultaneous cleavage of Sn-O and Si-O bonds, invariably yielding Ph₂SnO, Ph₃SiX, and the corresponding organo-mercury, -antimony, and -tellurium derivatives. The course of the reactions suggests the instability of the Sn-O-M (M = Hg, Sb, Te) system.

GRAPHICAL ABSTRACT      

Green synthesis of naphtho[2,3-f]quinolin-13-one and naphtho[2,3-a]acridin-1(2H)-one derivatives catalyzed by heteropoly acid supported montmorillonite K-10 clay

Herein, synthesis of a series of naphtho[2,3-f]quinolin-13-one and naphtho[2,3-a]acridin-1(2H)-one derivatives directly by one-pot multi-component reaction of 1,3-dicarbonyl compounds (1,3-indanedione/1,3-cyclohexanedione), 2-aminoantharacene/2-naphthylamine and various substituted aldehydes under solvent-free conditions using heteropoly-11-molybdo-1-vanadophosphoric acid supported on montmorillonite K-10 clay catalyst (10% PVMoK-10) is reported. The successful formation of naphtho[2,3-f]quinolin-13-one and naphtho[2,3-a]acridin-1(2H)-one derivatives was confirmed by various spectroscopic techniques. This study offers a green approach for the synthesis of novel quinolinone derivatives.     

Improved measurements and analysis of the far-infrared spectrum of methanol-D1 (CH2DOH) arising from trans- (e0) to gauche- (e1 & o1) states

In this work the millimeter-wave (MMW) and far infrared (FIR) absorption spectrum for the asymmetrically deuterated Methanol (CH₂DOH) species measured recently at a temperature of −60 °C with better accuracy and signal/noise (S/N) ratio than known before has been assigned for transitions originating at the lowest lying trans- to gauche-states. The entire spectrum for 50–1200 cm⁻¹ has been re-recorded recently using the Synchrotron Radiation Source coupled with the Bruker Fourier Transform Infrared (FTIR) spectrometer with a resolution of about 0.001 cm⁻¹ or better. Complete spectrum has not been exploited a great deal but it helped to entangle overlapping lines in the present work. This also fills the gap remaining in the usual FTIR in the range 400–500 cm⁻¹. Hence it is expected to help the interacting partner for the Coriolis interaction encountered earlier. The assigned transitions mostly for the axial rotational angular momentum quantum number K + 1 ← K, both for R- and Q-sub bands for wide range of rotational angular momentum quantum number. The MMW spectrum has been recalibrated and assigned for a number of Q-branches. The assignments are confirmed rigorously using closed loop residual technique. The assigned ^rR and ^rQ lines have been analyzed in terms of polynomial expansion parameters. The new assignments are presented for about 750 transitions and a grand atlas of more than 1000 lines has been prepared which will be made available through the open source server at “research gate”. The present work should be useful in the area of astrophysical detection and further understanding of the energy relaxation pathways in the molecule.     

Self-assembly of Mo<Subscript> 6</Subscript>S<Subscript> 8</Subscript> clusters on the Au(111) surface

The preferred adsorption sites and the propensity for a self-organised growth of the molybdenum sulfide cluster Mo₆S₈ on the Au(111) surface are investigated by density-functional band-structure calculations with pseudopotentials and a plane wave basis set. The quasi-cubic cluster preferentially adsorbs via a face and remains structurally intact. It experiences a strong, mostly non-ionic attraction to the surface at several quasi-isoenergetic adsorption positions. A scan of the potential energy surface exhibits only small barriers between adjacent strong adsorption sites. Hence, the cluster may move in a potential well with degenerate local energy minima at room temperature. The analysis of the electronic structure reveals a negligible electron transfer and S-Au hybridised states, which indicate that the cluster-surface interaction is dominated by S-Au bonds, with minor contributions from the Mo atom in the surface vicinity. All results indicate that Mo₆S₈ clusters on the Au(111) surface can undergo a template-mediated self-assembly to an ordered inorganic monolayer, which is still redox active and may be employed as surface-active agent in the integration of noble metal and ionic or biological components within nano-devices. Therefore, a classical potential model was developed on the basis of the DFT data, which allows to study larger cluster assemblies on the Au(111).     

高功率半导体激光端面泵浦方形掺Nd3+离子激光晶体热形变研究

为了解决高功率半导体激光器端面泵浦激光晶体引起的热效应问题,激光晶体泵浦端面的热形变必须进行准确的计算.通过对于全固态激光器中激光晶体的工作特点分析,建立了矩形截面激光晶体热分析模型.基于热传导方程,提出了泊松方程的一种新解,并获得了矩形截面激光晶体端面热形变分布的一般解析表达式.同时讨论了半导体激光器偏心泵浦激光晶体给端面热形变带来的影响.与有限元分析方法以及其他数值分析方法相比,解析分析方法不会给计算引入任何的误差.热形变的解析分析为解决激光晶体的热效应问题以及提高激光器的性能提供了理论的依据.     

Synthesis, Structure and Photoluminescence of a New Cd(Ⅱ)Coordination Polymer Based on 4-(Carboxymethoxy)-benzoic Acid and 1,10-Phenanthroline Derivative

A new 1D coordination polymer, [Cd2(L1)2(L2)2]·H2O (1, H2L1 = 4-(carboxy-methoxy)benzoic acid and L2 = 2-(4-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), has been hydrothermally synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a = 9.985(5), b = 10.768(5), c = 12.512(5), α = 68.959(5), β = 80.354(5), γ = 79.663(5)°, V = 1227.4(10) 3, Z = 1, C56H36Cd2F2N8O11, Mr = 1259.73, Dc = 1.704 g/cm3, F(000) = 630, μ(MoKa) = 0.949 mm-1, R = 0.0261 and wR = 0.0655. The L1 anions link the neighboring Cd(II) atoms to form a 1D double chain structure. The L2 ligands are alternately located on both sides of the double chains. More interestingly, the lateral L2 ligands from adjacent double chains are paired to furnish strong π-π interactions, yielding a 2D supramolecular layer. N-H···O, O-H···N and O-H···O hydrogen bonds further stabilize the structure of 1. The luminescent property of 1 was studied in solid state at room temperature.     

一维链状锌配位聚合物[Zn(Pyphen)(PZDC)(H2O)]的水热合成、结构与荧光性质

The title coordination polymer, [Zn(Pyphen)(PZDC)(H2O)] (1) (Pyphen=pyrazino [2,3-f][1,10]phen-anthroline and H2PZDC=pyrazine-2,3-dicarboxylic acid) has been obtained by using hydrothermal synthesis andcharacterized by elemental analysis, IR, TG, fluorescence spectrum and X-ray diffraction single-crystal structureanalysis. The crystal is of triclinic, space group P1 with a=0.681 8(14) nm, b=0.743 9(15) nm, c=1.759 8(35) nm,α=94.329(30)°,β=95.514(30)°,γ=97.043(3)°,V=0.878 2(3)nm3,Z=2,Mr=481.73,Dc=1.822 g·cm-2,μ=1.452 mm-1,F(000)=448, Rint=0.033 9, R=0.042 5, wR=0.090 7. In complex 1, PZDC ligands link the Zn(Ⅱ) ions to form 1Dchain structures, and further extended into a 3D supramolecular framework through π-π interactions andhydrogen bonding interactions. In addition, complex 1 exhibits strong photoluminescence at room temperature.