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 Mid-infrared feed-forward dual-comb spectroscopy

2019 ◽  
Vol 116 (9) ◽  
pp. 3454-3459 ◽  
Author(s):  
Zaijun Chen ◽  
Theodor W. Hänsch ◽  
Nathalie Picqué
Keyword(s):  
Molecular Spectroscopy ◽  
Signal To Noise Ratio ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Mid Infrared ◽  
Frequency Combs ◽  
Line Shapes ◽  
Frequency Scale ◽  
Invaluable Tool ◽  
Spectral Profiles

Mid-infrared high-resolution spectroscopy has proven an invaluable tool for the study of the structure and dynamics of molecules in the gas phase. The advent of frequency combs advances the frontiers of precise molecular spectroscopy. Here we demonstrate, in the important 3-µm spectral region of the fundamental CH stretch in molecules, dual-comb spectroscopy with experimental coherence times between the combs that exceed half an hour. Mid-infrared Fourier transform spectroscopy using two frequency combs with self-calibration of the frequency scale, negligible contribution of the instrumental line shape to the spectral profiles, high signal-to-noise ratio, and broad spectral bandwidth opens up opportunities for precision spectroscopy of small molecules. Highly multiplexed metrology of line shapes may be envisioned.

scholarly journals A Simulation Study of the Far-Infrared Absorption Spectra of HCl Diluted in Liquid Ar

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
A. Padilla ◽  
J. Pérez
Keyword(s):  
Infrared Absorption ◽  
High Frequency ◽  
Ad Hoc ◽  
Far Infrared ◽  
Rotational Spectra ◽  
Line Shapes ◽  
Thermodynamic Conditions ◽  
Spectral Profiles ◽  
Classical Quantum ◽  
Fitting Parameters

The far-infrared absorption coefficient of HCl diluted in liquid Ar has been calculated by using a mixed classical-quantum stochastic simulation approach. The simulated spectra have been compared with the available experimental data at different thermodynamic conditions without using ad hoc fitting parameters. Despite the fact that some discrepancies can be observed in the high frequency side of the far-infrared bands, a reasonable agreement has been found between the theoretical and the experimental spectral profiles. Both, classical and quantum simulated line shapes were comparatively analyzed, determining the time scales involved in the rotational spectra.

Quantum calculations of inelastic scattering of HCN and HNC by Ar

1996 ◽  
Vol 88 (1) ◽  
pp. 21-32 ◽  
Author(s):  
JOEL BOWMAN ◽  
D.ANNAPURNA PADMAVATHI
Keyword(s):  
Inelastic Scattering ◽  
Quantum Calculations

H NMR Evidence for a Change in The Local Hydrogen Environment of Sites Associated with the Staebler-Wronski Effect in a-Si:H

2002 ◽  
Vol 715 ◽  
Author(s):  
T. Su ◽  
Robin Plachy ◽  
P. C. Taylor ◽  
S. Stone ◽  
G. Ganguly ◽  
...  
Keyword(s):  
Line Shape ◽  
Defect Density ◽  
Hydrogen Atoms ◽  
Hydrogen Environment ◽  
H Nmr ◽  
Line Shapes ◽  
Different Temperatures ◽  
Staebler Wronski Effect

AbstractWe study the H NMR line shapes of a sample of a-Si:H under several conditions: 1) as grown, 2) light-soaked for 600 hours, and 3) light-soaked followed by annealing at different temperatures. At T = 7 K, the NMR line shape of the sample after light soaking exhibits an additional doublet compared to that of the sample as-grown. This doublet is an indication of a closely separated hydrogen pair. The distance between the two hydrogen atoms is estimated to be about (2.3 ± 0.2) Å. The concentration of these hydrogen sites is estimated to be between 1017 and 1018 cm-3 consistent with ESR measurements of the defect density after light soaking. This doublet disappears after the sample is annealed at 200°C for 4 hours.

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