Interference effects in the infrared absorption of solid hydrogen due to localized electrons

1987 ◽  
Vol 65 (1) ◽  
pp. 58-66 ◽  
Author(s):  
S. K. Bose ◽  
J. D. Poll
Keyword(s):  
State Transition ◽  
Bound State ◽  
Solid Hydrogen ◽  
Electronic Transitions ◽  
Detailed Calculation ◽  
Vibrational Transition ◽  
Nearest Neighbour ◽  
Interference Effects ◽  
Broad Absorption ◽  
Molecular Dipole

Recent experiments on proton-irradiated solid hydrogen show a broad absorption in the spectral region 4000–8000 cm−1. This broad absorption has been interpreted as being due to the lowest bound-state transition of electrons localized in cavitylike states in the lattice. Superposed on this broad spectrum is an asymmetric line, which is centered around the Stark-shifted fundamental vibrational transition (ν = 0 → ν = 1) of the molecules in the nearest neighbour positions with respect to the localized center of the electron. We present a detailed calculation of this line shape and show that the asymmetry can be attributed to the interference between the dipole of the localized electron and the charge-induced molecular dipole, as a result of a coincidence in the energies of the molecular and the electronic transitions.

Interference effects in the charge-induced spectrum of H2 at 4.2 K

1985 ◽  
Vol 63 (7) ◽  
pp. 937-940 ◽  
Author(s):  
R. L. Brooks ◽  
J. L. Hunt ◽  
Jack R. MacDonald ◽  
J. D. Poll ◽  
J. C. Waddington
Keyword(s):  
Absorption Spectrum ◽  
Proton Beam ◽  
Infrared Absorption ◽  
Infrared Absorption Spectrum ◽  
Electronic Transitions ◽  
Interference Effects ◽  
Molecular Dipole ◽  
Nearest Neighbours ◽  
Localized Electrons

The fundamental vibrational infrared-absorption spectrum of solid H2 at 4.2 K has been measured while the sample was irradiated with a 15-MeV proton beam. The Stark-shifted molecular transitions resulting from molecules that are the nearest neighbours of localized electrons have been observed and are contrasted with the same transition previously observed in solid D2. The differences are interpreted as evidence of an interference between the dipole of the localized electron and the charge-induced molecular dipole, a result of a coincidence in the frequencies of the molecular and electronic transitions.

Observation of new lines in the microwave spectrum of ortho-H2 pairs in solid hydrogen

1980 ◽  
Vol 58 (9) ◽  
pp. 1326-1340 ◽  
Author(s):  
B. W. Statt ◽  
W. N. Hardy ◽  
R. Jochemsen
Keyword(s):  
Solid Hydrogen ◽  
Microwave Spectrum ◽  
State Transitions ◽  
Nearest Neighbour ◽  
Microwave Spectrometer ◽  
Nearest Neighbours ◽  
Out Of Plane ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Potential Parameters

New microwave absorption spectra of ortho pairs in low ortho concentration samples of solid hydrogen are reported. Three excited state transitions which fix the position of the 10 Γ level for both types of nearest neighbour pairs are reported, and compared with the theoretical predictions of Harris, Berlinsky, and Hardy and Luryi and Van Kranendonk. Several new lines from the out-of-plane configuration are reported which confirm previous assignments. In contrast, two new lines from the next nearest neighbour spectrum support a reassignment of transitions for this configuration. A fit to this data determines several of the anisotropic potential parameters for next nearest neighbours. The improvements in the microwave spectrometer essential to obtaining the new results are also described. Finally, we compare our results to the most recent theoretical potential parameters of Schaefer and Meyer. A long standing discrepancy between theoretical and experimental values for the phonon renormalizationof Γ appears to be resolved by use of the new potential which has a substantial (~10%) non-quadrupolar contribution to ε4(R).

Infrared absorption by localized electrons in solid deuterium

1985 ◽  
Vol 63 (8) ◽  
pp. 1105-1109 ◽  
Author(s):  
S. K. Bose ◽  
J. D. Poll
Keyword(s):  
Infrared Absorption ◽  
Electronic States ◽  
Bound State ◽  
State Transitions ◽  
Cavity Size ◽  
Broad Absorption ◽  
Solid Deuterium ◽  
Mode Oscillation ◽  
Different Types ◽  
Energy Bound

A broad absorption in the spectral region 4000–7500 cm−1 has been observed in tritiated as well as proton-irradiated samples of solid deuterium. To explain this absorption we investigate two different types of localized electronic states in the solid. It is shown that the absorption can be interpreted as being due to the lowest energy bound-state transitions of electrons localized in nonspherical cavities of two different average radii. The localization is assumed to be initiated by vacancies. The shape of the absorption line is calculated by estimating the cavity size and the frequency of the breathing-mode oscillation of these cavities.

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