Development and construction of rotating polarizer analyzer ellipsometer

A detailed mathematical derivation and an experimental characterization of one to two ratio rotating polarizer analyzer ellipsometer (RPAE) are presented. The alignment, calibration, and testing of reference samples are also discussed. The optical properties of some known materials obtained by the proposed ellipsometer will be shown and compared to accepted values. Moreover, the constructed ellipsometer will be tested using two ellipsometry standards with different thicknesses.     

Rotating polarizer,compensator, and analyzer ellipsometry

In this paper we propose theoretically a set of ellipsometric configurations using a rotating polarizer, compensator, and analyzer at a speed ratio of N1ω：N2ω：N3ω. Different ellipsometric configurations can be obtained by giving different integral values to N1, N2, and N3. All configurations are applied to bulk c-Si and GaAs to calculate the real and imaginary parts of the refractive index of the samples. The accuracies of all ellipsometric configurations are investigated in the presence of a hypothetical noise and with small misalignments of the optical elements. Moreover, the uncertainties in the ellipsometric parameters as functions of the uncertainties of the Fourier coefficients are studied. The comparison among different configurations reveals that the rotating compensator–analyzer configuration corresponds to the minimum error in the calculated optical parameters.     

Dynamic plastic behavior of structures under impact loading investigated by the extended hamilton's principle

We propose the extended Hamilton's principle to investigate the dynamic plastic behavior of a beam or a plate under an impact loading. Material is assumed to be rigid perfectly plastic. The impact loading is given in the form of initial velocity. Good agreement between our numerical solutions and experimental results done by Parkes and Jones indicates that the proposed variational method is a powerful approximation method for the dynamic plasticity analysis. The effect of strain-rate sensitivity on the permanent deflection of a plate is investigated in some detail. Instead of nonlinear differential equations, nonlinear algebraic equations are solved in the proposed method.     

Photonic crystal with epsilon negative and double negative materials as an optical sensor

Two ternary photonic crystals are proposed for sensing applications. The first one is composed of an air layer as an analyte sandwiched between two double negative material (DNM) layers whereas the second one consists of an air layer sandwiched between two epsilon negative material (ENM) layers. The transmission spectrum is studied for two different values of the refractive index of the analyte layer with ?n = 0.01. A specific peak in the transmission spectrum is observed and the wavelength at which the peak occurs is determined. The wavelength shift due to any change in the index of the analyte layer is also determined. The effect of varying the parameters of the DNM and ENM on the sensitivity of the sensor is discussed. It is found that the sensitivity of the structure ENM/air/ENM is much greater than that of the structure DNM/air/DNM and it is estimated as 26 times of the sensitivity of the latter structure.     

Dichiral [4.4.3.01,5]tridecane copper(II) cluster derived from a tripodal ligand having unsymmetrical podands and the linker: Synthesis,structure, surface grafting and catalytic aspects

Pseudo‐atranes have a significant role in catalysis; however, obtaining chiral pseudo‐atranes for covalent functionalization of heterogeneous catalytic surfaces is very challenging. Herein, synthesis of a chiral tripodal amine [N{CH (CH₂Ph)CH₂OH}{CH₂(4? Br? C₆H₃OH)}{CH₂(2? CHO? 4? Me? C₆H₂OH)}] ( 1 ) and a dichiral [4.4.3.0^1,5]tridecane copper(II) cluster, that is, (Cu[N{CH (CH₂Ph)CH₂OH}{CH₂(4? Br? C₆H₃O)}{CH₂(2? CHO? 4? Me? C₆H₂O)}])₂ ( 2 ) is described. The compounds are characterized by elemental analyses, Fourier transform infrared (FT‐IR) spectroscopy, mass spectrometry and single‐crystal X‐ray crystallography (for 2 ). The compound 2 is the first example of chiral pseudo‐copper(II)atrane in which three unsymmetrical arms (two phenolic and a chiral ethanolic arm) are fused via Cu? N transannular bond. The free ? CHO group present in one of the tricyclic arms of the 2 is tested as a linker to load it on 3‐aminopropyltriethoxysilane‐functionalized magnetic nanosilica for catalytic applications. The loading of 2 on magnetic nanosilica through ? CHO was confirmed by FT‐IR spectroscopy, and the 2 ‐loaded magnetic nanosilica ( Fe ₃ O ₄ @SiO ₂ /2 ) was characterized by powder X‐ray diffraction, vibrating sample magnetometry, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and elemental mapping. The Fe ₃ O ₄ @SiO ₂ /2 was found highly efficient, retrievable, eco‐friendly and green catalyst for obtaining β‐amino alcohols in excellent yields in an aqueous medium. Overall, present work is the first report on synthetic, structural and catalytic aspects of dichiral cluster of copper(II)atrane possessing unsymmetrical tricyclic arms.     

Rotating polarizer analyzer ellipsometer with a fixed compensator

Recently, a rotating polarizer analyzer ellipsometer (RPAE) in which the two optical elements rotate in opposite directions with the same angular speed has been proposed. Calculated optical constants of some materials obtained from this ellipsometric configuration were in good agreement with published values except in the low photon energy regime. We here improve the structure by adding a fixed compensator after the rotating polarizer. The optical constants of c-Si calculated from the noisy signal in the low energy regime show a high reduction in the percent error when compared to that obtained from the previous structure that does not contain the fixed compensator.     

A parallelized integral-direct second-order Møller–Plesset perturbation theory method with a fragment molecular orbital scheme

We propose a parallelized integral-direct algorithm of the second-order Møller–Plesset perturbation theory (MP2) as a size-consistent correlated method. The algorithm is a modification of the recipe by Mochizuki et al. [(1996) Theor Chim Acta 93:211]. There is no need to communicate the bulky data of integrals across worker processes, keeping the formal fifth-power dependence on the number of basis functions. A multiple integral screening procedure is incorporated to reduce the operation costs effectively. An approximate MP2 density matrix can also be directly calculated through the integral contraction with orbital energies. We implement the MP2 code by accepting Kitauras fragment molecular orbital (FMO) scheme as in the program ABINIT-MP developed by Nakano et al. [(2002) Chem Phys Lett 351:475]. The error in the FMO–MP2 energies is found to be within the order of the chemical accuracy. Timing and parallel acceleration results are shown for test molecules.     

Deviations of capacitive and inductive loops in the electrochemical impedance of a dissolving iron electrode.

The electrochemical impedance of an iron electrode often shows the capacitive and inductive loops on the complex plane. The capacitive loop originates from the time constant of the charge transfer resistance and the electric double layer capacitance. The inductive loop is explained by Faradaic processes involving the reaction intermediate. In some cases, these loops deviate from a true semicircle. In this paper, the origins and curve-fitting methods for the deviated loops of electrochemical impedance are discussed. The constant phase element (CPE) was used to present the deviation of the capacitive loop instead of electric double layer capacitance. The reaction rate constants, which are a function of the frequency, are proposed for the Faradaic impedance to present the deviated inductive loop.