Raman and resonance-Raman spectra of polypyrrole with application to sensor – gas probe interactions

1995 ◽  
Vol 73 (10) ◽  
pp. 1711-1718 ◽  
Author(s):  
Stephen J. Vigmond ◽  
Vida Ghaemmaghami ◽  
Michael Thompson
Keyword(s):  
Gas Phase ◽  
Raman Spectra ◽  
Relative Intensity ◽  
Electronic States ◽  
Wave Number ◽  
High Wave Number ◽  
High Wave ◽  
Resonance Raman Spectra ◽  
Neutral Polymer ◽  
Wave Number Region

Raman spectra of the oxidized and neutral forms of polypyrrole show a relative intensity shift from the high wave number region to the low wave number region as the source wavelength is increased from 514.5 to 1064 nm. Variations in band positions are also observed with changes in excitation source; particularly, two C=C stretches at 1500 and 1605 cm−1 can be observed with the neutral polymer but only a single band is observed at 1575 cm−1 when sources of higher energy are used. These changes arise from differences in the electronic states of the two forms that can greatly alter the intensities of the numerous bands. The oxidized and neutral forms of the polymer both act as electron acceptors towards the gas phase species tested here (toluene, water, methanol, and ammonia). The increased electron density induces an upward shift of the peaks at 915 and 1035 cm−1 of the neutral polymer and increases the relative intensity of the 1575 cm−1 peak of the oxidized polymer using 1064 and 514.5 nm sources, respectively. Keywords: polypyrrole, Raman spectroscopy, gas probe interactions.

Aperture averaging of optical scintillations based on a spectrum with high wave number bump

1995 ◽  
Vol 34 (1) ◽  
pp. 26 ◽  
Author(s):  
Erich L. Bass
Keyword(s):  
Wave Number ◽  
High Wave Number ◽  
High Wave ◽  
Aperture Averaging

Resonance raman spectra of Br2 adsorbed on low-temperature solid surfaces: Excitation profile extending to the region above the dissociation limit in the gas phase

1989 ◽  
Vol 157 (1-2) ◽  
pp. 55-59 ◽  
Author(s):  
Takeo Matsushima ◽  
Yoshiyuki Onai ◽  
Kazuo Kasatani ◽  
Masahiro Kawasaki ◽  
Hiroyasu Sato
Keyword(s):  
Low Temperature ◽  
Gas Phase ◽  
Raman Spectra ◽  
Resonance Raman ◽  
Solid Surfaces ◽  
Dissociation Limit ◽  
Excitation Profile ◽  
Resonance Raman Spectra

The Method of Fundamental Solutions for Solving Exterior Axisymmetric Helmholtz Problems with High Wave-Number

2013 ◽  
Vol 5 (04) ◽  
pp. 477-493 ◽  
Author(s):  
Wen Chen ◽  
Ji Lin ◽  
C.S. Chen
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Matrix Decomposition ◽  
Coefficient Matrix ◽  
Fundamental Solutions ◽  
Method Of Fundamental Solutions ◽  
Wave Number ◽  
High Wave Number ◽  
Memory Space ◽  
High Wave

AbstractIn this paper, we investigate the method of fundamental solutions (MFS) for solving exterior Helmholtz problems with high wave-number in axisymmetric domains. Since the coefficient matrix in the linear system resulting from the MFS approximation has a block circulant structure, it can be solved by the matrix decomposition algorithm and fast Fourier transform for the fast computation of large-scale problems and meanwhile saving computer memory space. Several numerical examples are provided to demonstrate its applicability and efficacy in two and three dimensional domains.

Metal-metal interactions in binuclear rhodium isocyanide complexes. Resonance Raman spectra of the 1Alg and Eu3A2u electronic states of tetrakis(1,3-diisocyanopropane)dirhodium(I)

1981 ◽  
Vol 103 (6) ◽  
pp. 1595-1596 ◽  
Author(s):  
Richard F. Dallinger ◽  
Vincent M. Miskowski ◽  
Harry B. Gray ◽  
William H. Woodruff
Keyword(s):  
Raman Spectra ◽  
Resonance Raman ◽  
Electronic States ◽  
Metal Interactions ◽  
Metal Metal ◽  
Resonance Raman Spectra

scholarly journals Stable and Accurate Filtering Procedures

2020 ◽  
Vol 82 (1) ◽  
Author(s):  
Tomas Lundquist ◽  
Jan Nordström
Keyword(s):  
Boundary Conditions ◽  
High Frequency ◽  
Wave Number ◽  
Main Concern ◽  
High Wave Number ◽  
High Wave ◽  
Artificial Dissipation ◽  
High Frequency Oscillations ◽  
Energy Bound ◽  
Energy Stable

AbstractHigh frequency errors are always present in numerical simulations since no difference stencil is accurate in the vicinity of the $$\pi $$π-mode. To remove the defective high wave number information from the solution, artificial dissipation operators or filter operators may be applied. Since stability is our main concern, we are interested in schemes on summation-by-parts (SBP) form with weak imposition of boundary conditions. Artificial dissipation operators preserving the accuracy and energy stability of SBP schemes are available. However, for filtering procedures it was recently shown that stability problems may occur, even for originally energy stable (in the absence of filtering) SBP based schemes. More precisely, it was shown that even the sharpest possible energy bound becomes very weak as the number of filtrations grow. This suggest that successful filtering include a delicate balance between the need to remove high frequency oscillations (filter often) and the need to avoid possible growth (filter seldom). We will discuss this problem and propose a remedy.

Determination of the tautomeric composition of adenine in the gas phase by vibrational spectroscopy methods: II. Analysis of resonance Raman spectra

2010 ◽  
Vol 109 (6) ◽  
pp. 853-860 ◽  
Author(s):  
T. G. Burova ◽  
G. N. Ten ◽  
V. V. Ermolenkov ◽  
R. S. Shcherbakov ◽  
I. K. Lednev
Keyword(s):  
Gas Phase ◽  
Raman Spectra ◽  
Vibrational Spectroscopy ◽  
Resonance Raman ◽  
Tautomeric Composition ◽  
Resonance Raman Spectra

scholarly journals A robust domain decomposition method for the Helmholtz equation with high wave number

2016 ◽  
Vol 50 (3) ◽  
pp. 921-944 ◽  
Author(s):  
Wenbin Chen ◽  
Yongxiang Liu ◽  
Xuejun Xu
Keyword(s):  
Helmholtz Equation ◽  
Domain Decomposition ◽  
Domain Decomposition Method ◽  
Mesh Size ◽  
Relaxation Parameter ◽  
Point Of View ◽  
Wave Number ◽  
Theoretical Point ◽  
High Wave Number ◽  
High Wave

In this paper we present a robust Robin−Robin domain decomposition (DD) method for the Helmholtz equation with high wave number. Through choosing suitable Robin parameters on different subdomains and introducing a new relaxation parameter, we prove that the new DD method is robust, which means the convergence rate is independent of the wave number k for kh = constant and the mesh size h for fixed k. To the best of our knowledge, from the theoretical point of view, this is a first attempt to design a robust DD method for the Helmholtz equation with high wave number in the literature. Numerical results which confirm our theory are given.

scholarly journals An absolutely stable $hp$-HDG method for the time-harmonic Maxwell equations with high wave number

2016 ◽  
Vol 86 (306) ◽  
pp. 1553-1577 ◽  
Author(s):  
Peipei Lu ◽  
Huangxin Chen ◽  
Weifeng Qiu
Keyword(s):  
Maxwell Equations ◽  
Wave Number ◽  
High Wave Number ◽  
High Wave ◽  
Time Harmonic
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