Direct Spectroscopic Evidence of Bound States of(H2)2Complexes at Low Temperatures

1964 ◽  
Vol 13 (26) ◽  
pp. 810-812 ◽  
Author(s):  
A. Watanabe ◽  
H. L. Welsh
Keyword(s):  
Low Temperatures ◽  
Bound States ◽  
Spectroscopic Evidence

PRESSURE-INDUCED INFRARED ABSORPTION OF GASEOUS HYDROGEN AND DEUTERIUM AT LOW TEMPERATURES: I. THE INTEGRATED ABSORPTION COEFFICIENTS

1965 ◽  
Vol 43 (5) ◽  
pp. 818-828 ◽  
Author(s):  
A. Watanabe ◽  
H. L. Welsh
Keyword(s):  
Fine Structure ◽  
Low Temperature ◽  
Infrared Absorption ◽  
Low Temperatures ◽  
Bound States ◽  
Gaseous Hydrogen ◽  
Absorption Coefficients ◽  
Spectroscopic Evidence ◽  
Mixture Formula ◽  
Path Lengths

The pressure-induced infrared absorption of the fundamental band of hydrogen, in the pure gas and in a H2–He mixture, and of deuterium was studied in the temperature range from 18 °K to 77 °K. Path lengths up to 13.6 m at 1 atm or somewhat higher were obtained in a multiple-traversal cell cooled by liquid hydrogen or nitrogen. The binary coefficient [Formula: see text] for hydrogen shows a rise at low temperature, indicating the existence of bound states predicted by theory for the (H2)2 complex. The effect is more pronounced for deuterium. For the H2–He mixture [Formula: see text] decreases monotonically with temperature, thus showing no evidence of bound states for H2–He pairs. Fine structure at the maxima of the pressure-induced band in hydrogen and deuterium gives direct spectroscopic evidence of bound states of (H2)2 and (D2)2 complexes at low temperatures.

Mössbauer-Effekt von 57Fe und 119Sn in Palladiumlegierungen verschiedenen Wasserstoff-Gehaltes

1969 ◽  
Vol 24 (8) ◽  
pp. 1258-1265 ◽  
Author(s):  
M Mahnig ◽  
E Wicke
Keyword(s):  
Electronic Structure ◽  
Electron Concentration ◽  
Low Temperatures ◽  
Bound States ◽  
Experimental Methods ◽  
Magnetic Behaviour ◽  
Band Model ◽  
Direct Relation ◽  
Lattice Constants ◽  
Specific Heats

AbstractThe isomer shifts of 57Fe and 119Sn in Pd/Fe and Pd/Sn alloys of different compositions have been studied as functions of hydrogen content. In both systems the isomer shifts start to increase steeply at hydrogen contents which bring up the electron concentration in the alloy to 0.55 additional electrons per metal atom (compared to pure Pd). In accordance with results from other experimental methods each Fe atom has been found to donate 3 and each Sn atom 3.5 electrons to the bands of the alloy. The increase of the isomer shift is shown to follow the rise of the Fermi level when the bands are filled up gradually. It can be correlated to Friedel's model of virtual bound states. The results obtained confirm the connections developed earlier between the absorption of hydro-gen and the electronic structure of Pd and its alloys. They agree with conclusions drawn from magnetic behaviour and from electronic specific heats at low temperatures. They do not verify, how-ever, a direct relation to the lattice constants in these systems. It is not yet obvious how to correlate our results with the value of 0.36 d-holes in pure Pd obtained recently from measurements of the de Haas-van Alphen effect; possible deviations from the rigid-band model are discussed.

Prototypical cyclohexane dimers: spectroscopic evidence for σ stacking at low temperatures

2020 ◽  
Vol 22 (2) ◽  
pp. 905-913 ◽  
Author(s):  
N. Ramanathan ◽  
Shubhra Sarkar ◽  
K. Sundararajan
Keyword(s):  
Infrared Spectroscopy ◽  
Low Temperatures ◽  
Matrix Isolation ◽  
Stacking Interactions ◽  
Spectroscopic Evidence

In this work, the first unambiguous spectroscopic evidence for the existence of σ stacking interactions in cyclohexane dimers has been provided using matrix isolation infrared spectroscopy.

scholarly journals DC Self-Field Critical Current in Superconductor/Dirac-Cone Material/Superconductor Junctions

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1554 ◽  
Author(s):  
Evgueni Talantsev
Keyword(s):  
Experimental Data ◽  
Low Temperatures ◽  
Bound States ◽  
Critical Currents ◽  
Research Groups ◽  
Dirac Cone ◽  
Data Description ◽  
Andreev Bound States ◽  
Basic Model ◽  
Electronic Wave Function

Recently, several research groups have reported on anomalous enhancement of the self-field critical currents, Ic(sf,T), at low temperatures in superconductor/Dirac-cone material/superconductor (S/DCM/S) junctions. Some papers attributed the enhancement to the low-energy Andreev bound states arising from winding of the electronic wave function around DCM. In this paper, Ic(sf,T) in S/DCM/S junctions have been analyzed by two approaches: modified Ambegaokar-Baratoff and ballistic Titov-Beenakker models. It is shown that the ballistic model, which is traditionally considered to be a basic model to describe Ic(sf,T) in S/DCM/S junctions, is an inadequate tool to analyze experimental data from these type of junctions, while Ambegaokar-Baratoff model, which is generally considered to be a model for Ic(sf,T) in superconductor/insulator/superconductor junctions, provides good experimental data description. Thus, there is a need to develop a new model for self-field critical currents in S/DCM/S systems.

scholarly journals Pseudo-scalar mesons at finite temperatures from a Dyson-Schwinger-Bethe-Salpeter approach

2019 ◽  
Vol 204 ◽  
pp. 08005
Author(s):  
Sergey Dorkin ◽  
Leonid Kaptari ◽  
Burkhard Kämpfer
Keyword(s):  
Low Temperatures ◽  
Vertex Function ◽  
Bound States ◽  
Quark Propagator ◽  
Ladder Approximation ◽  
Zero Temperature ◽  
Interaction Kernel ◽  
Gap Equation ◽  
Scalar Mesons ◽  
Pseudo Scalar

The truncated Dyson-Schwinger–Bethe-Salpeter equations are employed at non-zero temperature. The truncations refer to a rainbow-ladder approximation augmented with an interaction kernel which facilitates a special temperature dependence. At low temperatures, T → 0, we recover a quark propagator from the Dyson-Schwinger (gap) equation smoothly interpolating to the T = 0 results. Utilizing that quark propagator we evaluate the Bethe-Salpeter vertex function in the pseudo-scalar qq̅ channel for the lowest boson Matsubara frequencies and find a competition of qq̅ bound states and quasi-free two-quark states at T = O (100 MeV).

Direct Spectroscopic Evidence of Bound States of H2–Ar Complexes at 100°K

1965 ◽  
Vol 43 (9) ◽  
pp. 3397-3398 ◽  
Author(s):  
A. Kudian ◽  
H. L. Welsh ◽  
A. Watanabe
Keyword(s):  
Bound States ◽  
Spectroscopic Evidence

Recent Radiative and Collisional Atomic Data of Astrophysical Interest

1988 ◽  
Vol 102 ◽  
pp. 129-132
Author(s):  
K.L. Baluja ◽  
K. Butler ◽  
J. Le Bourlot ◽  
C.J. Zeippen
Keyword(s):  
Mass Production ◽  
Bound States ◽  
Physical Models ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Isoelectronic Sequence ◽  
Astrophysical Interest ◽  
Radiative Transitions ◽  
Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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