Quantum calculations for line shapes in Raman spectra of molecular nitrogen

1996 ◽  
Vol 104 (19) ◽  
pp. 7590-7598 ◽  
Author(s):  
Sheldon Green ◽  
Winifred M. Huo
Keyword(s):  
Raman Spectra ◽  
Molecular Nitrogen ◽  
Quantum Calculations ◽  
Line Shapes

scholarly journals Fano Resonance Line Shapes in the Raman Spectra of Tubulin and Microtubules Reveals Active Quantum Effects

2022 ◽  
pp. 100043
Author(s):  
Wenxu Zhang ◽  
Travis J.A. Craddock ◽  
Yajuan Li ◽  
Mira Swartzlander ◽  
Robert R. Alfano ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Fano Resonance ◽  
Resonance Line ◽  
Quantum Effects ◽  
Line Shapes

Theoretical and experimental studies of high-resolution inverse Raman spectra of molecular nitrogen at 1-10 atm

1987 ◽  
Vol 91 (1) ◽  
pp. 41-46 ◽  
Author(s):  
M. L. Koszykowski ◽  
L. A. Rahn ◽  
R. E. Palmer ◽  
M. E. Coltrin
Keyword(s):  
High Resolution ◽  
Raman Spectra ◽  
Molecular Nitrogen ◽  
Experimental Studies

scholarly journals Far Wing Asymmetry of Rotational Raman Lines in Hydrogen

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Magnus Gustafsson
Keyword(s):  
Raman Spectra ◽  
Line Profile ◽  
Threshold Energy ◽  
Rotational Transition ◽  
Hydrogen Gas ◽  
Shape Resonance ◽  
Pure Hydrogen ◽  
Line Shapes ◽  
Significant Intensity

Depolarized Raman spectra of compressed hydrogen gas have been computed rigorously previously for 36 K and 50 K (Gustafsson et al. (2009)). The far wings of the rotational lines show asymmetry that goes beyond that expected from the theory for intracollisional interference and Fano line shapes. Here we analyze the (0) line for pure hydrogen at 36 K in detail. The added asymmetry stems partly from a shape resonance which adds significant intensity to the higher frequency side of the line profile. The influence of the threshold energy for the rotational transition accounts for the remainder.

Radiative and Chemical Kinetic Implications

2008 ◽  
Author(s):  
Adrian F. Tuck
Keyword(s):  
Molecular Oxygen ◽  
Water Vapour ◽  
Near Infrared ◽  
Molecular Nitrogen ◽  
Energy Levels ◽  
Far Infrared ◽  
Electromagnetic Spectrum ◽  
Radiative Balance ◽  
Line Shapes ◽  
Homonuclear Diatomic Molecules

The laws governing the dynamical behaviour of atoms and molecules are quantum mechanical, and specify that their internal energy states are discrete, with only definite photon energies inducing transitions between them, subject to selection rules. These energy levels appear as spectra in different regions of the electromagnetic spectrum: pure rotational lines in the microwave or far infrared, ‘rovibrational’ (rotation + vibration) lines in the middle and near infrared, while electronic transitions, sometimes with associated rotational and vibrational structure (‘rovibronic’) occur from the near infrared through the visible to the ultraviolet. An important feature of these spectra in the atmosphere is that they do not appear as single sharp lines, but are collisionally broadened about the central energy into ‘line shapes’ which frequently overlap with other transitions, both from the same molecule and from others. One of the primary dynamical quantities involved in the processes broadening these line shapes is the relative velocity of the molecules with which the photon absorbing and emitting molecules are colliding. These are primarily N2 and O2 in the atmosphere; if they have an overpopulation of fast moving molecules relative to a Maxwell–Boltzmann distribution, as we have suggested, the line shapes will be affected. Molecules such as carbon dioxide, water vapour, and ozone are all active in the infrared via rovibrational transitions, with water vapour being light enough and so having sufficiently rapid rotation that it has rotational bands appearing in the far infrared rather than the microwave. Nitrous oxide, N2O, and methane, CH4, are also active, but make smaller contributions because of their lower abundances. Molecular nitrogen and molecular oxygen, because they are homonuclear diatomic molecules, do not absorb or emit via electric dipole allowed transitions in the atmospherically important regions of the electromagnetic spectrum. Molecular oxygen, having a triplet ground state, does have weak forbidden and magnetic dipole transitions which, however, play only a very small role in the radiative balance. It should be noted that the translational energy of molecules in a large system like the atmosphere is effectively continuous rather than quantized.

Anomalous scattering and asymmetrical line shapes in Raman spectra of orthorhombic KNbO3

1976 ◽  
Vol 14 (11) ◽  
pp. 5068-5072 ◽  
Author(s):  
A. M. Quittet ◽  
M. I. Bell ◽  
M. Krauzman ◽  
P. M. Raccah
Keyword(s):  
Raman Spectra ◽  
Anomalous Scattering ◽  
Line Shapes

On the Digital Computer Method of Spectral Line Analysis

1979 ◽  
Vol 33 (3) ◽  
pp. 248-253 ◽  
Author(s):  
Hiroyasu Nomura ◽  
Shinobu Koda ◽  
Yutaka Miyahara
Keyword(s):  
Spectral Line ◽  
Raman Spectra ◽  
Present Method ◽  
Least Squares Method ◽  
Nonlinear Least Squares ◽  
Analytical Form ◽  
Computational Method ◽  
Line Shapes ◽  
Nonlinear Least Squares Method ◽  
Experimental Values

A new digital computational method of spectral line shape analysis is reported. In the present method, the parameters of object functions are directly found to fit the experimental values on the basis of a nonlinear least squares method. The present method is available for curve fitting of experimental results if the functions are expressed in analytical form. As an example, the results of resolving the recorded Raman spectra into the component line shapes is presented. The agreement of the recorded Raman spectra with that composed of the resolved lines is excellent.

Modelling the far wings of collision-induced translational spectral profiles

2001 ◽  
Vol 79 (5) ◽  
pp. 801-811 ◽  
Author(s):  
W Glaz ◽  
G C Tabisz
Keyword(s):  
Quantum Calculations ◽  
Line Shapes ◽  
Langevin Approach ◽  
Spectral Profiles ◽  
Cohen Model

By comparing three model spectral profiles to precise line shapes obtained from quantum calculations, we assess the suitability of the various models for describing the far wings of translational collision-induced spectra. A profile obtained based on a generalized Langevin approach can give a better fit to the quantum shape than the widely used Birnbaum–Cohen model; the fit given by the six-parameter extended Birnbaum–Cohen profile proves to be the best of all three functions. PACS No.: 32.70Jz

scholarly journals Breit-Wigner-Fano line shapes in Raman spectra of graphene

2014 ◽  
Vol 90 (24) ◽  
Author(s):  
Eddwi H. Hasdeo ◽  
Ahmad R. T. Nugraha ◽  
Mildred S. Dresselhaus ◽  
Riichiro Saito
Keyword(s):  
Raman Spectra ◽  
Line Shapes

Collisional narrowing and spectral shift in coherent anti-stokes Raman spectra of molecular nitrogen up to 2500 bar and 700 K

1990 ◽  
Vol 50 (6) ◽  
pp. 527-533 ◽  
Author(s):  
Th. Bouch� ◽  
Th. Dreier ◽  
B. Lange ◽  
J. Wolfrum ◽  
E. U. Franck ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Molecular Nitrogen ◽  
Spectral Shift ◽  
Anti Stokes
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