scholarly journals Observation of quantum dynamical resonances in near cold inelastic collisions of astrophysical molecules

2016 ◽  
Vol 7 (4) ◽  
pp. 2462-2469 ◽  
Author(s):  
Michel Costes ◽  
Christian Naulin
Keyword(s):  
Inelastic Collisions ◽  
Quantum Dynamical ◽  
Quantum Resonances ◽  
Beam Experiment ◽  
Low Energies ◽  
Astrophysical Molecules

Quantum resonances in inelastic collisions, predicted by theory and detected at low energies in a crossed-beam experiment, are reviewed.

Inelastic collisions at low energies

1969 ◽  
Vol 47 (10) ◽  
pp. 1723-1729 ◽  
Author(s):  
A. Dalgarno
Keyword(s):  
Energy Loss ◽  
Cross Sections ◽  
Low Energy ◽  
Inelastic Collisions ◽  
Low Energies ◽  
Low Energy Electrons ◽  
The Cross ◽  
Loss Rates

A summary is presented of the processes by which low energy electrons lose energy in moving through the atmosphere and estimates are given of the cross sections and energy loss rates. The mechanisms by which thermal electrons cool are described and the cooling efficiencies are listed.

Quantum dynamical resonances in low-energy CO(j = 0) + He inelastic collisions

2015 ◽  
Vol 7 (4) ◽  
pp. 349-353 ◽  
Author(s):  
Astrid Bergeat ◽  
Jolijn Onvlee ◽  
Christian Naulin ◽  
Ad van der Avoird ◽  
Michel Costes
Keyword(s):  
Low Energy ◽  
Inelastic Collisions ◽  
Quantum Dynamical

scholarly journals Inelastic collisions of interstellar molecules

1997 ◽  
Vol 178 ◽  
pp. 241-252 ◽  
Author(s):  
J.J. Ter Meulen
Keyword(s):  
Cross Sections ◽  
Molecular Beam ◽  
Inelastic Collisions ◽  
Quantum Calculations ◽  
Initial State ◽  
Detection Techniques ◽  
Rotational Energy Transfer ◽  
Beam Experiment ◽  
State Selection ◽  
Good Agreement

The rotational energy transfer of NH3, OH and D2CO in inelastic collisions with He and H2 is studied in a crossed molecular beam experiment. The molecules are prepared in a single initial state by rotational cooling in an adiabatic expansion followed by electrostatic state selection. Relative state-to-state cross sections are determined by measuring the collision induced redistribution of the population of the initial state by using state selective laser detection techniques. The results for NH3 and OH are compared to theoretical values obtained from quantum calculations. Except for NH3 — He where theory predicts a parity selection rule for transitions to the 33 and 43 states, which is not observed in the experiment, good agreement between experiment and theory is obtained.

Inelastic collisions between ions and atoms

1952 ◽  
Vol 212 (1109) ◽  
pp. 235-248 ◽  
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Negative Ions ◽  
Inelastic Collisions ◽  
Electron Affinities ◽  
Atomic Collision ◽  
Low Energies ◽  
Low Energy Electron ◽  
The Cross

Charge-exchange cross-sections for H + , D + , O + 2 , H + 2 , O + , CO + and N + 2 in A; D + , O + and N + in Kr; D + , C + and Br + in Xe, and O + in H 2 O have been measured between 25 and 4000 eV energy by a method previously described. The normal atomic collision cross-sections rise to a maximum at a voltage which depends on the value of Δ E √ M for the process, M being the atomic mass and Δ E the energy defect of the reaction. Collisions between negative ions and atoms have been studied with the same apparatus, the cross-section of the detachment reaction X - + Y → X + e + Y — Δ E being obtained. For S - , Br - , I - , C - , P - , Li - in Ne, and H - in He, Ne, A, Kr, Xe, this rises with increasing energy of the incident ion. For O - in He, Ne, A, Kr, Xe, Cl - in He, Ne, A, Kr, Xe, and F - in Ne, Kr, Xe the cross-section at low energies is unexpectedly large for the value of Δ E √M. This may be interpreted as being due to the presence of excited states of these ions, of low electron affinities, in the beam. With O - , a low energy electron bombardment source gave smaller cross-sections, i.e. a smaller proportion of excited ions.

Fresnel interference in point-projection imaging of purple membrane

1995 ◽  
Vol 53 ◽  
pp. 846-847
Author(s):  
X. Zhang ◽  
J. Spence ◽  
W. Qian ◽  
D. Taylor ◽  
K. Taylor
Keyword(s):  
Detection Efficiency ◽  
Mean Free Path ◽  
Purple Membrane ◽  
Unit Cell Dimension ◽  
Experimental Point ◽  
Membrane Thickness ◽  
Low Energies ◽  
Channel Plate ◽  
Point Projection ◽  
Inelastic Mean Free Path

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

Electrical Damage Due to Low Energy Plasma Processing of GaAs Structures

1991 ◽  
Vol 223 ◽  
Author(s):  
Hans P. Zappe ◽  
Gudrun Kaufel
Keyword(s):  
Chemical Processes ◽  
Low Energy ◽  
Electrical Behavior ◽  
Rapid Thermal Anneal ◽  
High Temperature Anneal ◽  
Significant Damage ◽  
Low Energies ◽  
Long Time ◽  
Physical Plasma

ABSTRACTThe effect of numerous plasma reative ion etch and physical milling processes on the electrical behavior of GaAs bulk substrates has been investigated by means of electric microwave absorption. It was seen that plasma treatments at quite low energies may significantly affect the electrical quality of the etched semiconductor. Predominantly physical plasma etchants (Ar) were seen to create significant damage at very low energies. Chemical processes (involving Cl or F), while somewhat less pernicious, also gave rise to electrical substrate damage, the effect greater for hydrogenic ambients. Whereas rapid thermal anneal treatments tend to worsen the electrical integrity, some substrates respond positively to long-time high temperature anneal steps.

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