Theoretical progress and challenges in dissociative recombination

2006 ◽  
Vol 364 (1848) ◽  
pp. 2965-2980 ◽  
Author(s):  
Chris H Greene ◽  
V Kokoouline
Keyword(s):  
Storage Ring ◽  
Reasonable Agreement ◽  
Dissociative Recombination ◽  
Low Energy ◽  
Recombination Rates ◽  
Interstellar Clouds ◽  
Theoretical Progress ◽  
Jahn Teller ◽  
Theory And Experiment

We discuss the Jahn–Teller mechanism for dissociative recombination in low energy collisions between electrons and ions, in energy ranges relevant to the processes underway in interstellar clouds. While theory has become capable of predicting recombination rates in reasonable agreement with storage ring experiments, some discrepancies remain with them, and a long-standing discrepancy with stationary afterglow measurements remains troubling. Speculations about the desirable improvements in both theory and experiment are presented.

Effects of molecular rotation in low-energy electron collisions of

2006 ◽  
Vol 364 (1848) ◽  
pp. 2981-2997 ◽  
Author(s):  
Andreas Wolf ◽  
H Kreckel ◽  
L Lammich ◽  
D Strasser ◽  
J Mikosch ◽  
...  
Keyword(s):  
Storage Ring ◽  
Recombination Rate ◽  
Rate Coefficient ◽  
Dissociative Recombination ◽  
Spin Symmetry ◽  
Low Energy ◽  
Magnetic Storage ◽  
Electron Collisions ◽  
Theoretical Predictions ◽  
Recombination Rate Coefficient

Measurements on the energetic structure of the dissociative recombination rate coefficient in the millielectronvolt range are described for ions produced in the lowest rotational levels by collisional cooling and stored as a fast beam in the magnetic storage ring TSR (Test Storage Ring). The observed resonant structure is consistent with that found previously at the storage ring facility CRYRING in Stockholm, Sweden; theoretical predictions yield good agreement on the overall size of the rate coefficient, but do not reproduce the detailed structure. First studies on the nuclear spin symmetry influencing the lowest level populations show a small effect different from the theoretical predictions. Heating processes in the residual gas and by collisions with energetic electrons, as well as cooling owing to interaction with cold electrons, were observed in long-time storage experiments, using the low-energy dissociative recombination rate coefficient as a probe, and their consistency with the recent cold measurements is discussed.

Enhancement of electron–ion recombination rates at low energy range in the heavy ion storage ring CSRm

2020 ◽  
Vol 29 (3) ◽  
pp. 033401 ◽  
Author(s):  
Nadir Khan ◽  
Zhong-Kui Huang ◽  
Wei-Qiang Wen ◽  
Shu-Xing Wang ◽  
Han-Bing Wang ◽  
...  
Keyword(s):  
Energy Range ◽  
Storage Ring ◽  
Heavy Ion ◽  
Low Energy ◽  
Recombination Rates ◽  
Ion Storage ◽  
Ion Recombination

scholarly journals Low-energy electron impact dissociative recombination and vibrational transitions of N2+

2021 ◽  
Vol 129 (5) ◽  
pp. 053303
Author(s):  
A. Abdoulanziz ◽  
C. Argentin ◽  
V. Laporta ◽  
K. Chakrabarti ◽  
A. Bultel ◽  
...  
Keyword(s):  
Electron Impact ◽  
Dissociative Recombination ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron ◽  
Vibrational Transitions

scholarly journals Low-Energy Optical Conductivity of TaP: Comparison of Theory and Experiment

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 567
Author(s):  
Alexander Yaresko ◽  
Artem V. Pronin
Keyword(s):  
Experimental Data ◽  
Optical Conductivity ◽  
Low Energy ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Natural Explanation ◽  
Weyl Semimetal ◽  
Unintentional Doping ◽  
Mott Formula ◽  
Theory And Experiment

The ab-plane optical conductivity of the Weyl semimetal TaP is calculated from the band structure and compared to the experimental data. The overall agreement between theory and experiment is found to be best when the Fermi level is slightly (20 to 60 meV) shifted upwards in the calculations. This confirms a small unintentional doping of TaP, reported earlier, and allows a natural explanation of the strong low-energy (50 meV) peak seen in the experimental ab-plane optical conductivity: this peak originates from transitions between the almost parallel non-degenerate electronic bands split by spin-orbit coupling. The temperature evolution of the peak can be reasonably well reproduce by calculations using an analog of the Mott formula.

Unbalance Response of a Dual Rotor System: Theory and Experiment

1993 ◽  
Vol 115 (4) ◽  
pp. 427-435 ◽  
Author(s):  
K. Gupta ◽  
K. D. Gupta ◽  
K. Athre
Keyword(s):  
System Theory ◽  
Transfer Matrix ◽  
Mode Shape ◽  
Reasonable Agreement ◽  
Complex Variables ◽  
Rotor System ◽  
Experimental Results ◽  
Unbalance Response ◽  
Theoretical Results ◽  
Theory And Experiment

A dual rotor rig is developed and is briefly discussed. The rig is capable of simulating dynamically the two spool aeroengine, though it does not physically resemble the actual aeroengine configuration. Critical speeds, mode shape, and unbalance response are determined experimentally. An extended transfer matrix procedure in complex variables is developed for obtaining unbalance response of dual rotor system. Experimental results obtained are compared with theoretical results and are found to be in reasonable agreement.

ROLE OF THE ELECTRON–PHONON INTERACTION ON THE SPECTRAL DENSITY AND PSEUDOGAP IN CUPRATES

2002 ◽  
Vol 16 (23) ◽  
pp. 3465-3471
Author(s):  
I. CHAUDHURI ◽  
S. K. GHATAK
Keyword(s):  
Critical Temperature ◽  
Spectral Density ◽  
Low Energy ◽  
Phonon Interaction ◽  
Energy Excitation ◽  
Electron Phonon Interaction ◽  
Peak Structure ◽  
Electronic Model ◽  
Jahn Teller

The pseudogap structure in low energy excitation in cuprates appears below a temperature and the spectral density exhibits strong wave-vector dependence. An electronic model that emphasized the coupling of carrier in Cu-O with phonon is examined for pseudogap. The electron–phonon interaction originates from the modulation of on-site and hopping energy and leads to spontaneous Jahn–Teller-like distortion and pseudogap below a critical temperature. At low temperature the spectral density has two-peak structure about the Fermi level for all k along Γ-M whereas such structure exists along Γ-X for small k only. The magnitude of pseudogap shows strong k-dependence — maximum along Γ-M and vanishes along Γ-X. These features emphasize the role of electron–phonon interaction in formation of pseudogap.

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