Interference effects in the spectrum of HD: III. The pure rotational band at 77 K for HD and HD–Ne mixtures

1984 ◽  
Vol 62 (12) ◽  
pp. 1673-1679 ◽  
Author(s):  
A. R. W. McKellar ◽  
J. W. C. Johns ◽  
W. Majewski ◽  
N. H. Rich
Keyword(s):  
Dipole Moment ◽  
Rotational Band ◽  
Reasonable Agreement ◽  
Permanent Dipole Moment ◽  
Destructive Interference ◽  
Interference Effects ◽  
Constructive Interference ◽  
Fundamental Band ◽  
A Value

The pure rotational R(0) transition of HD has been studied in pure HD and in HD–Ne mixtures at a temperature of 77 K and at densities between 3 and 123 amagat. Limited measurements of R(1) in pure HD were also made. A value of 8.18 ± 0.26 D was obtained for the R(0) permanent dipole moment of HD, in reasonable agreement with the theoretical value of 8.3 D. However, no evidence for destructive collisional interference effects at high densities was found, and in fact a slight constructive interference was noted. Thus, these results stand in contrast with those for the fundamental band, and with other recent experiments on the pure rotational band, in which destructive interference was invariably measured.

Interference effects in the spectrum of HD: IV: the pure rotational band at room temperature

1986 ◽  
Vol 64 (3) ◽  
pp. 227-231 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Spectral Resolution ◽  
Rotational Band ◽  
Path Length ◽  
Room Temperature ◽  
Dipole Transition ◽  
Rotational Spectrum ◽  
Density Range ◽  
Interference Effects ◽  
Fundamental Band ◽  
Line Strengths

The rotational spectrum of HD has been studied in absorption at room temperature for a density range of 6–57 amagat. Spectra were obtained in the 170- to 360-cm−1 region, including the R0(1), R0(2), and R0(3) transitions, with a 1-m path length and a spectral resolution varying from 0.05 to 0.20 cm−1. The observed line strengths were used to determine values for the dipole transition moments of HD in the range of 7.4 to 7.8 × 10−4 D, which is somewhat lower than currently accepted theoretical values of about 8.3–8.4 × 10−4 D. Only very small effects (≈0.2% per amagat) were found due to collisional interference on the line strengths; this result contrasts with much larger interference effects observed in the fundamental band, and it also casts some doubt on other recent studies of the rotational spectrum where larger interference effects were reported.

Intercollisional Interference in the S Lines of H2–He Mixtures

1975 ◽  
Vol 53 (10) ◽  
pp. 954-961 ◽  
Author(s):  
J. D. Poll ◽  
J. L. Hunt ◽  
J. W. Mactaggart
Keyword(s):  
Dipole Moment ◽  
Line Shape ◽  
Short Range ◽  
Experimental Results ◽  
Strength Parameter ◽  
Free Molecule ◽  
Fundamental Band ◽  
A Value ◽  
Induced Dipole ◽  
Interference Minimum

Further experimental results on the pressure induced spectrum of normal H2–He in the region of the S(1) branch of the fundamental band are presented. These results show a well-defined minimum at the transition frequency of the free molecule. The S line is found to be the sum of two components. One of these is of essentially the same nature as the Q branch and should therefore show a pronounced intercollisional interference minimum. The second component shows the usual quadrupolar line shape without a minimum. Finally, a value for the strength parameter characterizing the short range component of the induced dipole moment is determined.

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.

scholarly journals Stationary Wave Interference and Its Relation to Tropical Convection and Arctic Warming

2016 ◽  
Vol 29 (4) ◽  
pp. 1369-1389 ◽  
Author(s):  
Michael Goss ◽  
Steven B. Feldstein ◽  
Sukyoung Lee
Keyword(s):  
Sea Ice ◽  
Stationary Wave ◽  
Warm Pool ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Boreal Winter ◽  
Destructive Interference ◽  
Constructive Interference ◽  
Sea Ice Concentration ◽  
Stratospheric Polar Vortex

Abstract The interference between transient eddies and climatological stationary eddies in the Northern Hemisphere is investigated. The amplitude and sign of the interference is represented by the stationary wave index (SWI), which is calculated by projecting the daily 300-hPa streamfunction anomaly field onto the 300-hPa climatological stationary wave. ERA-Interim data for the years 1979 to 2013 are used. The amplitude of the interference peaks during boreal winter. The evolution of outgoing longwave radiation, Arctic temperature, 300-hPa streamfunction, 10-hPa zonal wind, Arctic sea ice concentration, and the Arctic Oscillation (AO) index are examined for days of large SWI values during the winter. Constructive interference during winter tends to occur about one week after enhanced warm pool convection and is followed by an increase in Arctic surface air temperature along with a reduction of sea ice in the Barents and Kara Seas. The warming of the Arctic does occur without prior warm pool convection, but it is enhanced and prolonged when constructive interference occurs in concert with enhanced warm pool convection. This is followed two weeks later by a weakening of the stratospheric polar vortex and a decline of the AO. All of these associations are reversed in the case of destructive interference. Potential climate change implications are briefly discussed.

Interference effects in the spectrum of HD: I. The fundamental band of pure HD

1983 ◽  
Vol 61 (12) ◽  
pp. 1648-1654 ◽  
Author(s):  
N. H. Rich ◽  
A. R. W. McKellar
Keyword(s):  
Absorption Spectrum ◽  
Dipole Moment ◽  
Phase Shift ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
High Density ◽  
Line Profiles ◽  
Interference Effects ◽  
Permanent Electric Dipole Moment ◽  
Precise Interpretation

The absorption spectrum of the ν = 1 ← 0 band of HD has been investigated at a temperature of 77 K and for densities in the range of 15 to 140 amagat. The band consists of two components: a broad collision-induced quasi continuum arising from dipoles induced during molecular collisions; and a dipole-allowed part arising from the small permanent electric dipole moment of the free HD molecule. The interference effects which occur between these two components were studied for the dipole-allowed R1(0) and R1(1) transitions. These transitions exhibited increasingly large asymmetries and changes in intensity at high density, but their behaviours were quite different from each other. The shape of each transition could be well represented by a series of Fano line profiles, and the evolution of shape and intensity with density could be accounted for by the formulation of Herman, Tipping, and Poll. However, the precise interpretation of the phase shift parameters arising in the theory is not clear.

The permanent dipole moment of ScF

1991 ◽  
Vol 176 (3-4) ◽  
pp. 303-308 ◽  
Author(s):  
Benoit Simard ◽  
Michael Vasseur ◽  
Peter A. Hackett
Keyword(s):  
Dipole Moment ◽  
Permanent Dipole Moment

Joint time-variant spectral analysis — Part 1: Forward modeling the effects of thin-bed layering

2018 ◽  
Vol 6 (4) ◽  
pp. T967-T983
Author(s):  
Ramses G. Meza ◽  
J. Antonio Sierra ◽  
John P. Castagna ◽  
Umberto Barbato
Keyword(s):  
Seismic Data ◽  
Seismic Isolation ◽  
Forward Modeling ◽  
Destructive Interference ◽  
Constructive Interference ◽  
Phase Component ◽  
Time Frequency ◽  
Seismic Wavelet ◽  
Specific Frequency ◽  
Net To Gross

Using time-frequency and time-phase analysis we found that for an isolated thin bed in a binary-impedance setting, there is no observable sensitivity in preferential illumination as layered net-to-gross (NTG) changes within the isolated thin bed, regardless of the way the internal layering is distributed — either uniformly or semirandomly. The NTG signature is observed on the amplitude (magnitude) responses, rather than any specific frequency or phase component. On the other hand, external mutual thin-bed interference can significantly change the preferred phase component for each participating target. This phenomenon is largely driven by the embedded seismic wavelet that determines the nominal seismic response of an isolated thin layer and what phase component would preferentially illuminate it. For vertical separations between mutually interfering and elastically comparable thin beds in which mutual constructive interference is achieved, the target bed will be preferentially illuminated at a phase component that is very close to that of a total seismic isolation, whereas the occurrence of mutual destructive interference will cause a significant departure on the phase preferential illumination from that of an isolated seismic thin bed. All these observations can provide an avenue to yield more robust stratigraphic interpretations of seismic data and enhance the confidence on subsurface description.

scholarly journals The Role of Polarizabilities in the Fluorescence Behaviour of 4-cyano-N,N-dimethylaniline

1981 ◽  
Vol 36 (8) ◽  
pp. 868-875 ◽  
Author(s):  
Wolfram Baumann
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
External Electric Field ◽  
Ground State ◽  
Permanent Dipole Moment ◽  
Reaction Field

Abstract The effect of an external electric field on the absorption and the double fluorescence of 4-cyano-N,N-dimethylaniline can be understood, taking into account reaction field induced polarizability effects. If a TICT state conformation emits the a-fiuorescence in dioxane, the permanent dipole moment in this state is only slightly larger than in the equilibrium ground state.

scholarly journals Enhancement of and interference among higher order multipole transitions in molecules near a plasmonic nanoantenna

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Evgenia Rusak ◽  
Jakob Straubel ◽  
Piotr Gładysz ◽  
Mirko Göddel ◽  
Andrzej Kędziorski ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Electric Dipole ◽  
Electric Quadrupole ◽  
Coherence Time ◽  
Dipole Approximation ◽  
Higher Order ◽  
Destructive Interference ◽  
Interference Effects ◽  
Matter Coupling ◽  
Molecular Transition

AbstractSpontaneous emission of quantum emitters can be modified by their optical environment, such as a resonant nanoantenna. This impact is usually evaluated under assumption that each molecular transition is dominated only by one multipolar channel, commonly the electric dipole. In this article, we go beyond the electric dipole approximation and take light-matter coupling through higher-order multipoles into account. We investigate a strong enhancement of the magnetic dipole and electric quadrupole emission channels of a molecule adjacent to a plasmonic nanoantenna. Additionally, we introduce a framework to study interference effects between various transition channels in molecules by rigorous quantum-chemical calculations of their multipolar moments and a consecutive investigation of the transition rate upon coupling to a nanoantenna. We predict interference effects between these transition channels, which allow in principle for a full suppression of radiation by exploiting destructive interference, waiving limitations imposed on the emitter’s coherence time by spontaneous emission.

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