Vibrational excitation cross section and V → T rate constants in molecular hydrogen

1979 ◽  
Vol 38 (1) ◽  
pp. 97-108 ◽  
Author(s):  
F.A. Gianturco ◽  
U.T. Lamanna
Keyword(s):  
Cross Section ◽  
Rate Constants ◽  
Molecular Hydrogen ◽  
Excitation Cross Section ◽  
Vibrational Excitation

scholarly journals A Study of the Vibrational Excitation of H2 by Measurements of the Drift Velocity of Electrons in H2−Ne Mixtures

1988 ◽  
Vol 41 (4) ◽  
pp. 573 ◽  
Author(s):  
JP England ◽  
MT Elford ◽  
RW Crompton
Keyword(s):  
Cross Section ◽  
Drift Velocity ◽  
Cross Sections ◽  
Excitation Cross Section ◽  
Vibrational Excitation ◽  
Pure Hydrogen ◽  
Velocity Data ◽  
Highly Sensitive ◽  
Hydrogen Mixtures ◽  
Made In

Measurements of electron drift velocities have been made in 1�160% and 2�892% hydrogen-neon mixtures at 294 K and values of EI N from 0�12 to 1�7 Td. The measurements are highly sensitive to the region of the threshold of the v = 0 → 1 vibrational excitation cross section for hydrogen and have enabled more definitive tests of proposed cross sections to be made than was possible using drift velocity data for H2−He and H2−Ar mixtures. The theoretical v = 0 → 1 vibrational excitation cross section of Morrison et al. (1987) is shown to be incompatible with the present measurements. A new set of hydrogen cross sections has been derived from the available electron swarm measurements in pure hydrogen and hydrogen mixtures.

scholarly journals Vibrational Excitation Cross-Section by Positron Impact: A Wave-Packet Dynamics Study

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 64
Author(s):  
Luis A. Poveda ◽  
Marcio T. do N. Varella ◽  
José R. Mohallem
Keyword(s):  
Wave Packet ◽  
Cross Section ◽  
Energy Surface ◽  
Excitation Cross Section ◽  
Vibrational Mode ◽  
Vibrational Excitation ◽  
Spherically Symmetric ◽  
Positron Impact ◽  
Wave Packet Dynamics ◽  
Good Agreement

The vibrational excitation cross-section of a diatomic molecule by positron impact is obtained using wave-packet propagation techniques. The dynamics study was carried on a two-dimensional potential energy surface, which couples a hydrogenlike harmonic oscillator to a positron via a spherically symmetric correlation polarization potential. The cross-section for the excitation of the first vibrational mode is in good agreement with previous reports. Our model suggests that a positron couples to the target vibration by responding instantly to an interaction potential, which depends on the target vibrational coordinate.

Exchange effects in the rotational excitation of molecular hydrogen by slow electrons

1968 ◽  
Vol 304 (1479) ◽  
pp. 465-477 ◽  
Keyword(s):  
Cross Section ◽  
Molecular Hydrogen ◽  
Excitation Cross Section ◽  
Rotational Excitation ◽  
Distorted Wave ◽  
Single Centre ◽  
Wave Approximation ◽  
Exchange Effects ◽  
Slow Electrons ◽  
Electron Energy Loss

The scattering formalism of Arthurs & Dalgarno (1960) is generalized to take account of exchange (but not polarization) in the scattering of slow electrons by molecular hydrogen. The use of a single-centre molecular wavefunction is discussed, and representative calcula­tions of the j = 0→ j = 2 rotational excitation cross-section are carried out in the distorted wave approximation. The inclusion of exchange results in a significant increase (rising from 12% at 0.1 eV to over 70% at 0.5 eV) in the dominant ( p -wave) contribution to the cross-section. It is concluded that exchange effects cannot be ignored in the theoretical discussion of electron energy loss by rotational excitation in swarm experiments.

A Poor Man’s Approach to Semi-Quantitative Analysis with Electron Energy Loss Spectroscopy

1980 ◽  
Vol 38 ◽  
pp. 110-111
Author(s):  
M. Isaacson
Keyword(s):  
Quantitative Analysis ◽  
Energy Loss ◽  
Electron Energy ◽  
Cross Section ◽  
Electron Energy Loss Spectroscopy ◽  
Excitation Cross Section ◽  
Incident Electron ◽  
Integral Cross Section ◽  
Image Position ◽  
Electron Energy Loss

In an earlier paper1 it was found that to a good approximation, the efficiency of collection of electrons that had lost energy due to an inner shell excitation could be written as where σE was the total excitation cross-section and σE(θ, Δ) was the integral cross-section for scattering within an angle θ and with an energy loss up to an energy Δ from the excitation edge, EE. We then obtained: where , with P being the momentum of the incident electron of velocity v. The parameter r was due to the assumption that d2σ/dEdΩ∞E−r for energy loss E. In reference 1 it was assumed that r was a constant.

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