scholarly journals Calculation of the vibrational linewidth and line shape of Raman spectra using the relaxation function. I. Method and application to nitrogen

2000 ◽  
Vol 112 (3) ◽  
pp. 1395-1403 ◽  
Author(s):  
M. Eline Kooi ◽  
Floris Smit ◽  
Jan P. J. Michels ◽  
Jan A. Schouten
Keyword(s):  
Raman Spectra ◽  
Line Shape ◽  
Relaxation Function

Breit-Wigner-Fano Lineshape Analysis of the angential G-band of Metallic Nanotubes

2000 ◽  
Vol 633 ◽  
Author(s):  
Sandra D. Brown ◽  
Ado Jorio ◽  
Paola Corio ◽  
Mildred Dresselhaus ◽  
Gene Dresselhaus ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Raman Spectra ◽  
Line Shape ◽  
Frequency Component ◽  
Lineshape Analysis ◽  
Raman Study ◽  
Resonant Raman ◽  
Band Spectra ◽  
Lorentzian Lineshape ◽  
Diameter Distributions

AbstractWe present a resonant Raman study of the tangential G-band in metallic SWNTs. By measuring the Raman spectra for isolated SWNTs, we show that the two different lineshapes observed for semiconducting and metallic SWNTs in bundles also occur for isolated SWNTs. A lineshape analysis of the tangential G-band feature for metallic SWNT bundles is presented, showing that only two components are present, the higher frequency component having a Lorentzian lineshape, and the lower one having a Breit–Wigner–Fano (BWF) line-shape. Through comparisons of the Raman tangential G-band spectra from three different diameter distributions of carbon nanotubes, we find that both the frequency and linewidth of the BWF component are diameter dependent.

Line shape analysis of the Raman spectrum of diamond films grown by hot-filament and microwave-plasma chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2456-2468 ◽  
Author(s):  
Lawrence H. Robins ◽  
Edward N. Farabaugh ◽  
Albert Feldman
Keyword(s):  
Raman Spectra ◽  
Raman Line ◽  
Line Shape ◽  
Shape Function ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Defect Structures ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Hot Filament

Raman spectra were taken of 48 polycrystalline diamond films grown by hot-filament and microwave-plasma chemical vapor deposition (CVD), and one gem-quality diamond, and characterized by fitting the spectra to a model line shape function. The line shape function contains three components: a narrow symmetric line at ∼1333 cm−1, the Raman line of diamond; a band centered at ∼1525 cm−1 ascribed to sp2-bonded carbon; and a broad background due to photoluminescence (PL). Four spectral parameters were observed to change from one specimen to another in an interrelated manner: (1) the linewidth of the diamond Raman line, which varies from ∼3 to ∼25 cm−1; (2) the intensity in the tails of the diamond Raman line, several halfwidths away from the peak; (3) the peak intensity ratio of the sp2-bonded carbon band to the diamond Raman line, which varies from ∼0 to ∼1; and (4) the intensity ratio of the PL background to the diamond Raman peak, which varies from ∼0.03 to ∼9. We suggest that the interrelated changes in the Raman spectra are due to changes in the abundance of sp2-bonded defect structures within the diamond crystallites. Polynuclear aromatic clusters are a possible model for these defect structures. Differences in film morphology, which were observed by SEM imaging, appear to be correlated with the changes in the Raman spectra. The peak position of the diamond Raman line is shifted to higher wave number in the CVD-grown films than in the gem, by as much as 3 cm−1, but this shift is not correlated with the other changes in the Raman spectra. As a function of deposition conditions, the defect-related features of the Raman spectra generally increase with increasing methane concentration or substrate temperature, and decrease with increasing oxygen concentration. A cyclic dependence of the defect-related features on deposition time is observed for one set of films grown by hot-filament CVD.

Investigation of Acetic Acid Hydration Shell Formation through Raman Spectra Line-Shape Analysis

2012 ◽  
Vol 116 (44) ◽  
pp. 13219-13227 ◽  
Author(s):  
Francesco D’Amico ◽  
Filippo Bencivenga ◽  
Alessandro Gessini ◽  
Emiliano Principi ◽  
Riccardo Cucini ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Raman Spectra ◽  
Shape Analysis ◽  
Line Shape ◽  
Hydration Shell ◽  
Shell Formation ◽  
Line Shape Analysis

scholarly journals Line shape analysis of the Raman spectra from pure and mixed biofuels esters compounds

Fuel ◽  
2014 ◽  
Vol 115 ◽  
pp. 118-125 ◽  
Author(s):  
Alisson M. Miranda ◽  
Eduardo W. Castilho-Almeida ◽  
Erlon H. Martins Ferreira ◽  
Gabriela F. Moreira ◽  
Carlos A. Achete ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Shape Analysis ◽  
Line Shape ◽  
Line Shape Analysis

A GAUSSIAN, NON-MARKOVIAN APPROACH TO LONG MEMORY WITH APPLICATION TO A STOCHASTIC THEORY OF LINE SHAPE

1993 ◽  
Vol 07 (13) ◽  
pp. 2539-2548 ◽  
Author(s):  
MARCEL OVIDIU VLAD
Keyword(s):  
Line Shape ◽  
Long Memory ◽  
Relaxation Function ◽  
Stochastic Theory ◽  
Random Variable ◽  
Memory Effects ◽  
Time Behavior ◽  
Long Time ◽  
Markovian Random Process ◽  
Markovian Approach

A new approach to long memory effects is suggested. The main assumption is that the regression of fluctuations occurs via a clustering mechanism. The regression of a scalar variable takes place through a succession of linear decay processes, resulting in a long time tail of the autocorrelation function. The number of decay events is a random variable obeying a self-similar probability distribution whose fractal exponent determines the long time behavior of fluctuation regression. The overall fluctuation dynamics is described by a stationary Gaussian and non-Markovian random process. The theory is applied to the stochastic theory of line shape. The relaxation function ϕ(t) can be exactly evaluated. We show that the memory effects lead to a narrowing of the relaxation function for large time. As the time t tends to infinity, ϕ(t) may be approximated by a ‘contracted’ exponential ϕ(t) ~ exp(-const. t2−H) where 1≥H>0 is the fractal exponent describing the clustering process.

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