Interference effects in the spectrum of HD: II. The fundamental band for HD–rare gas mixtures

1984 ◽  
Vol 62 (12) ◽  
pp. 1665-1672 ◽  
Author(s):  
A. R. W. McKellar ◽  
N. H. Rich
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Low Temperatures ◽  
Rare Gas ◽  
Interference Effects ◽  
Rare Gases ◽  
Physical Processes ◽  
Fundamental Band ◽  
Line Shapes ◽  
Collision Partner

The absorption spectrum of the fundamental band of HD (λ ≈ 2.7 μm) has been studied at high resolution in mixtures with the rare gases He, Ne, and Ar at low temperatures (77 and 145 K) and moderate densities (<205 amagat). Interference effects that occur between the collision-induced transitions and the dipole-allowed transitions of free HD were analyzed as a function of density and collision-partner. The R(0) and R(1)dipole transitions exhibited large changes in shape and intensity at high densities, but their behaviours were quite different from each other. Like the pure HD samples, the line shapes were well represented by series of Fano profiles, and the density dependences of the lines were well explained by the theory of Herman, Tipping, and Poll. These results should greatly improve the understanding of the physical processes underlying the interference effects.

Direct measurements of N2 broadened linewidths in the CO fundamental at low temperatures

1983 ◽  
Vol 61 (2) ◽  
pp. 192-197 ◽  
Author(s):  
J.-P. Bouanich ◽  
R. Farrenq ◽  
C. Brodbeck
Keyword(s):  
High Resolution ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Variable Temperature ◽  
Absorption Cell ◽  
Fundamental Band ◽  
Direct Measurements ◽  
High Resolution Spectrometer ◽  
Vibration Rotation ◽  
Resolution Spectrometer

The halfwidths of CO vibration–rotation lines, pressure-broadened by N2 have been measured in the fundamental band at −83, −148, and −180 °C, using a variable temperature absorption cell and a high resolution spectrometer. The temperature dependence of linewidths has been calculated from the Anderson–Tsao–Curnutte theory and compared to the experimental determinations.

Interference effects in the spectrum of HD: VI: HD–HD, and HD–Kr at room temperature

1994 ◽  
Vol 72 (5-6) ◽  
pp. 215-224 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Absorption Spectrum ◽  
Fourier Transform ◽  
High Resolution ◽  
Room Temperature ◽  
Dipole Transition ◽  
Interference Effects ◽  
Hydrogen Deuteride ◽  
Interference Phenomenon ◽  
Infrared Spectrometer ◽  
Line Positions

The absorption spectrum of the fundamental band of hydrogen deuteride (λ ≈ 2.7 μm) has been studied in pure HD and in mixtures with krypton at moderate densities (1–45 amagat) and room temperature, using a high-resolution Fourier transform infrared spectrometer. The effects that arise from interference between the allowed dipole transition moments of free HD and the dipoles induced during collisions were studied. For HD–HD collisions, the eight transitions from P1(3) to R1(4) were analyzed to determine line positions, intensities, shift and broadening coefficients, and the phase shift parameters that govern the interference effects. Thus the interference phenomenon was studied over a wider range of initial- and final-J values than previously possible, and the systematic dependence of the phase shifts on transition was determined. For HD–Kr collisions, the R1(0) and R1(1) transitions were examined in detail. The spectrum in the region of R1(1) exhibited a realtively broad underlying "plateau" feature that was shown to be due to the presence of impurity CF4 molecules in the Kr sample.

scholarly journals High-Resolution Photoabsorption Spectrum of Cs+ (5p61So + 5p5ns, nd) Between 504A and 600A using a Laser Ionized Cs Vapor Column

1984 ◽  
Vol 86 ◽  
pp. 124-124
Author(s):  
T.J. McIlrath ◽  
V. Kaufman ◽  
J. Sugar ◽  
W.T. Hill ◽  
D. Cooper
Keyword(s):  
High Resolution ◽  
Laser Pulse ◽  
High Voltage ◽  
Power Output ◽  
Random Phase ◽  
Grazing Incidence ◽  
Fano Resonances ◽  
Line Shapes ◽  
Phase Calculation ◽  
Photoabsorption Spectrum

Rapid ionization of Cs vapor in a heat pipe at 0.05 torr was achieved by pumping the 6s 2S½ – 7p 2P½ transition (f=0.007)1 with a flash-pumped dye laser at 4593.2A and I MW power output. Photoabsorptian initiated at the end of the laser pulse(≃ 0.5/s) showed the 5p5ns and nd series below and above the 5p52P3/2 threshold at 535.4A. Broad Beutler - Fano resonances appeared in the d series above threshold. The spectrum was recorded photographically on a 10.7m grazing incidence spectrograph using a continuum background generated by a BRV high-voltage spark source with a uranium anode. We will compare the line-shapes and the quantum defect (Lu-Fano2) plot with the predictions of a relativistic random phase calculation.

Instrumental Distortions of Raman Lines

1982 ◽  
Vol 36 (4) ◽  
pp. 424-427 ◽  
Author(s):  
A. K. Arora ◽  
V. Umadevi
Keyword(s):  
Low Temperatures ◽  
Full Width ◽  
Line Shapes ◽  
Peak Intensity ◽  
Empirical Relations ◽  
Extended Range ◽  
Main Component ◽  
Lorentzian Spectrum ◽  
True Peak ◽  
Better Than

The effect of spectrometer resolution on the peak intensity and the full width at half maximum (FWHM) of a Lorentzian spectrum is obtained by evaluating the convoluted line shapes. Spectrometer resolution functions (SRF) having Gaussian and triangular profiles are considered separately. Empirical relations to estimate the true peak intensity and the FWHM from the observed parameters are suggested. These relations are valid over an extended range of parameters with an accuracy better than that of other methods suggested earlier. As an application, the true FWHM's and peak intensities of the main component of the Raman active Ag mode of sulphate ion in potash alum at low temperatures are evaluated.

scholarly journals Probing Be star disks: new insights from Hα spectroscopy and detailed numerical models

2010 ◽  
Vol 6 (S272) ◽  
pp. 398-399 ◽  
Author(s):  
Carol E. Jones ◽  
Christopher Tycner ◽  
Jessie Silaj ◽  
Ashly Smith ◽  
T. A. Aaron Sigut
Keyword(s):  
High Resolution ◽  
Numerical Models ◽  
Analytical Tool ◽  
High Resolution Spectroscopy ◽  
Be Stars ◽  
Line Shapes ◽  
Physical Conditions ◽  
Temperature Distributions ◽  
Inclination Angles ◽  
Be Star

AbstractHα high resolution spectroscopy combined with detailed numerical models is used to probe the physical conditions, such as density, temperature, and velocity of Be star disks. Models have been constructed for Be stars over a range in spectral types and inclination angles. We find that a variety of line shapes can be obtained by keeping the inclination fixed and changing density alone. This is due to the fact that our models account for disk temperature distributions self-consistently from the requirement of radiative equilibrium. A new analytical tool, called the variability ratio, was developed to identify emission-line stars at particular stages of variability. It is used in this work to quantify changes in the Hα equivalent widths for our observed spectra.

Intercollisional interference at low temperatures

1985 ◽  
Vol 63 (1) ◽  
pp. 99-103
Author(s):  
John Courtenay Lewis
Keyword(s):  
Dipole Moment ◽  
Impact Parameter ◽  
Low Temperatures ◽  
Quantum Effect ◽  
Intermolecular Force ◽  
Fundamental Band ◽  
Induced Dipole ◽  
Binary Collisions

The intercollisional interference dip in the Q-branch of the fundamental band of collision-induced spectra of H2–He mixtures partially fills in at low temperatures. In contradiction to claims that this ia a quantum effect, we show 1. that if the induced dipole moment is exactly proportional to the intermolecular force then the interference dip goes to zero at all temperatures; 2. that the filling-in of the dip is essentially a classical phenomenon and is due mainly to the discontinuity in the distance of closest approach during binary collisions as a function of impact parameter.

High resolution studies of the system of 13C-formaldehyde

1979 ◽  
Vol 57 (10) ◽  
pp. 1676-1680 ◽  
Author(s):  
F. W. Birss ◽  
R. M. Gordon ◽  
D. A. Ramsay ◽  
S. M. Till
Keyword(s):  
Absorption Spectrum ◽  
High Resolution ◽  
Type B ◽  
Molecular Constants ◽  
Text Type ◽  
Type C

The absorption spectrum of H213CO has been photographed in the region 3600 to 3000 Å under high resolution. Rotational analyses have been carried out for four bands, viz., [Formula: see text], [Formula: see text], [Formula: see text] (Type B), and [Formula: see text] (Type C), and molecular constants are given. Several perturbations have been found and possible mechanisms discussed.

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