Interference effects in theR0(0) transition of solid HD

R. H. Tipping; J. D. Poll

doi:10.1103/physrevb.35.6699

Interference effects in the spectrum of HD: V. the pure rotational and fundamental bands of liquid HD

Canadian Journal of Physics ◽

10.1139/p87-001 ◽

1987 ◽

Vol 65 (1) ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

M. J. Clouter ◽

A. R. W. McKellar

Keyword(s):

Path Length ◽

Infrared Absorption Spectrum ◽

Far Infrared ◽

Moderate Pressure ◽

Interference Effects ◽

Mid Infrared ◽

Infrared Spectrometer ◽

Narrow Width ◽

Solid Hd ◽

Symmetric Shape

The infrared absorption spectrum of HD has been studied in the liquid phase at temperatures between 17 and 35 K. Results were obtained for the region of the pure rotational R0(0) transition in the far infrared (80–95 cm−1), and for the fundamental band in the mid infrared (3600–4000 cm−1), using a temperature-controlled moderate-pressure cell with a 1.5-cm path length and a Fourier-transform infrared spectrometer. The R0(0) line was found to have a symmetric shape, a rather narrow width (from 1.3 to 1.8 cm−1), and an intensity that is moderately enhanced by interference effects. The R1(0) transition was found to have a more complicated asymmetrie shape due to interference effects, and at low temperatures was found to consist of (at least) two components, which strongly resemble those observed in solid HD.

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A theoretical study of the fundamental absorption band of solid HD

Canadian Journal of Physics ◽

10.1139/p87-261 ◽

1987 ◽

Vol 65 (12) ◽

pp. 1577-1587 ◽

Cited By ~ 7

Author(s):

S. K. Bose ◽

J. D. Poll

Keyword(s):

Theoretical Study ◽

Direct Absorption ◽

Interference Effects ◽

Absorption Profile ◽

Transition Energies ◽

Double Excitation ◽

Vibrational Excitations ◽

Solid Hd ◽

Experimental Absorption

A theoretical study of absorption into the fundamental band of solid HD in the neighbourhood of the R1(0) transition is presented. The spectrum, calculated by using a one-phonon approximation, shows qualitative agreement with the experimental absorption curve in the region lying between the Q1(0) and R1(0) transition energies. In particular, we are able to show that the absorption at an energy immediately below that of the R1(0) peak should almost vanish, as observed in the experiment. The role of various dipoles as well as their interference effects is discussed. Such effects are found to be significant near the R1(0) transition peak. The influence of the double-excitation states, in which the rotational and the vibrational excitations reside on two different molecules, is considered. There is no direct absorption into such states, implying the lack of a Q1(0) + R0(0) peak in the spectrum. However, because these states are close in energy to those in which the vibrational and the rotational excitations reside on the same molecule, they somewhat modify the absorption spectrum in the region of the R1(0) peak. Away from this peak, the effect of the double-excitation states on the absorption profile is negligible.

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Some Aspects of Exelfs Analysis in the Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600000477 ◽

1980 ◽

Vol 38 ◽

pp. 118-119

Author(s):

D. E. Johnson ◽

S. Csillag

Keyword(s):

Fine Structure ◽

Electron Microscope ◽

Energy Loss ◽

Analytical Electron Microscopy ◽

Interference Effects ◽

Interatomic Distances ◽

X Ray ◽

Structure Information ◽

Microanalytical Technique ◽

Analytical Electron

Recently, the applications area of analytical electron microscopy has been extended to include the study of Extended Energy Loss Fine Structure (EXELFS). Modulations past an ionization edge in the energy loss spectrum (EXELFS), contain atomic fine structure information similar to Extended X-ray Absorbtion Fine Structure (EXAFS). At low momentum transfer the main contribution to these modulations comes from interference effects between the outgoing excited inner shell electron waves and electron waves backscattered from the surrounding atoms. The ability to obtain atomic fine structure information (such as interatomic distances) combined with the spatial resolution of an electron microscope is unique and makes EXELFS an important microanalytical technique.

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