scholarly journals Resonant excitation of molecules by low-energy electrons

2008 ◽  
Vol 6 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Goran Poparic
Keyword(s):  
Cross Sections ◽  
Valence State ◽  
Vibrational Excitation ◽  
Rydberg States ◽  
Low Energy ◽  
Resonant Excitation ◽  
Excitation Spectra ◽  
Energy Excitation ◽  
The Cross ◽  
Near Threshold

Low-energy electron impact vibrational and electronic excitation cross sections of the CO, N2 and CO2 molecules are measured by use of a high resolution crossed-beams double trochoidal electron spectrometer. The spectrometer is designed to work in standard and time-of-flight regimes. The energy dependences of the resonant vibrational excitation of the first several vibrational levels of the N2, CO, and CO2 molecules, have been measured. Characteristic substructures in energy excitation spectra in the cases of N2 and CO have been obtained and discussed for some vibrational channels for the first time. The ratio of forward-to-backward scattered electrons from the 2? resonance in CO is found to be equal to 1, and thus the angular distribution of scattered electrons to be symmetric relative to 90?. This conclusion supports the fact that the contribution of the p? partial wave is dominant in the energy region of the 2? resonance in CO. The energy dependences of the near threshold resonant excitation of the valence and Rydberg states of the N2 and CO molecules have been measured. The cross sections of the near threshold resonant excitation of the C 3?u valence state, and the E 3?+ g and a'' 1?+ g Rydberg states of the N2 molecule have been measured. In the case of the CO molecule, the cross sections of the near threshold resonant excitation of the a 3? valence state, and the b 3?+ and B 1?+ Rydberg states have been measured. Resonant structures in excitation functions of all measured electronic states are observed and their locations are compared with resonances obtained in different decay channels.

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.

scholarly journals The Cross Section for the J = 0 → 2 Rotational Excitation of Hydrogen by Slow Electrons

1969 ◽  
Vol 22 (6) ◽  
pp. 715 ◽  
Author(s):  
RW Crompton ◽  
DK Gibson ◽  
AI McIntosh
Keyword(s):  
Momentum Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
The Cross ◽  
Excitation Processes ◽  
Slow Electrons ◽  
And Diffusion ◽  
Momentum Transfer Cross Section ◽  
Section Analysis

The results of electron drift and diffusion measurements in parahydrogen have been analysed to determine the cross sections for momentum transfer and for rotational and vibrational excitation. The limited number of possible excitation processes in parahydrogen and the wide separation of the thresholds for these processes make it possible to determine uniquely the J = 0 → 2 rotational cross section from threshold to 0.3 eV. In addition, the momentum transfer cross section has been determined for energies less than 2 eV and it is shown that, near threshold, a vibrational cross section compatible with the data must lie within relatively narrow limits. The problems of uniqueness and accuracy inherent in the swarm method of cross section analysis are discussed. The present results are compared with other recent theoretical and experimental determinations; the agreement with the most recent calculations of Henry and Lane is excellent.

Low-energy excitation spectra of the system KY(MoO4)2-KEr(MoO4)2

1996 ◽  
Vol 46 (S5) ◽  
pp. 2687-2688
Author(s):  
Vladimir I. Kut'ko ◽  
Nina M. Nesterenko ◽  
Yuriy N. Kharchenko
Keyword(s):  
Low Energy ◽  
Excitation Spectra ◽  
Energy Excitation

scholarly journals Low Energy Excitation Spectra of Trapped Bose Condensates

1998 ◽  
Vol 93 (1) ◽  
pp. 211-235 ◽  
Author(s):  
L. You ◽  
W. Hoston ◽  
M. Lewenstein ◽  
M. Marinescu
Keyword(s):  
Low Energy ◽  
Excitation Spectra ◽  
Energy Excitation ◽  
Bose Condensates

Experimental Study of Low Energy e-O2 Collision Processes

1971 ◽  
Vol 26 (10) ◽  
pp. 1617-1625 ◽  
Author(s):  
F. Linder ◽  
H. Schmidt
Keyword(s):  
Angular Dependence ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
Resonance Scattering ◽  
Spectroscopic Constants ◽  
Extended Model ◽  
Vibrational Levels ◽  
Electronically Excited ◽  
The Cross ◽  
Electronic Ground

Abstract Elastic scattering, vibrational excitation to v=1, 2, 3, 4 of the electronic ground state, and electronic excitation to the states a1Δ g and b1Σg+ of O2 have been measured in a crossed beam apparatus for collision energies from nearly 0 eV to 4 eV. Differential and integral cross sections have been determined and calibrated on an absolute scale. From 15 vibrational levels of O2-, which could be observed as resonances in the cross sections, the spectroscopic constants for the vibrational structure of O2- have been derived: ωe = 135 meV and ωeχe = 1 meV. The cross sections for vibrational excitation have the order of 10-18 cm2. eV for the larger resonance peaks. Detailed cross sections have been listed in Table 1. The half width of the resonance can be estimated to Γ ≈ 0.5 meV, which corresponds to a lifetime tof 10-12 sec for the O2- states. The angular dependence of pure resonance scattering is rather flat and not in accordance with the simplest theoretical model. An analysis of the angular dependence and of the rotational structure of the resonance in a somewhat extended model have been performed. - No electronically excited O2-states could be detected in the energy range up to 3 eV.

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