scholarly journals THEORETICAL MODELS FOR ATOMIC CHARGE TRANSFER IN ION-ATOM COLLISIONS

1989 ◽  
Vol 04 (04) ◽  
pp. 769-844 ◽  
Author(s):  
D. H. JAKUBAßA-AMUNDSEN
Keyword(s):  
Cross Sections ◽  
Bound States ◽  
Atomic Charge ◽  
Theoretical Models ◽  
High Energy ◽  
Specific Model ◽  
Nuclear Resonance ◽  
Continuum States ◽  
High Energy Collisions ◽  
Capture Cross Sections

The current theoretical models for the description of electron transfer in adiabatic, intermediate and high-energy collisions are reviewed. Particular emphasis is laid on the recent development of atomic theories suited for fast or asymmetric ion-atom encounters. The comparison with other theories and with experimental data on total as well as differential capture cross sections is used to determine the applicability of a specific model. The selected examples concern capture to bound states, to continuum states, radiative transfer as well as capture in the presence of an isolated nuclear resonance.

scholarly journals Absolute cross sections for the dissociation of hydrogen cluster ions in high-energy collisions with helium atoms

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
S. Eden ◽  
J. Tabet ◽  
K. Samraoui ◽  
S. Louc ◽  
B. Farizon ◽  
...  
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Cluster Ions ◽  
Helium Atoms ◽  
High Energy Collisions

High energy photoionization of bound systems

2020 ◽  
Vol 35 (03) ◽  
pp. 2040021
Author(s):  
E. G. Drukarev ◽  
A. I. Mikhailov
Keyword(s):  
Cross Sections ◽  
Bound States ◽  
Wave Equations ◽  
High Energy ◽  
Central Field ◽  
Model Potentials

We demonstrate how the nonrelativistic high energy asymptotics for the photoionization cross sections of systems bound by a central field can be obtained without solving the wave equations. The earlier analysis carried out for s bound states is extended for p states. We show that the physically expected asymptotics for ionization of fullerenes is not reproduced by the model potentials employed nowadays.

scholarly journals Renormalised Perturbation Theory of Resonant Multiphoton Ionisation

1995 ◽  
Vol 48 (5) ◽  
pp. 835
Author(s):  
K Unnikrishnan
Keyword(s):  
Perturbation Theory ◽  
Cross Sections ◽  
Bound States ◽  
Resonance Region ◽  
Short Pulses ◽  
Total Cross Sections ◽  
Two Photon ◽  
Continuum States ◽  
The Mean ◽  
Good Agreement

Perturbation theory of multiphoton ionisation due to a classical electromagnetic field is modified to allow for intermediate resonances with bound states. Complex energies, generally associated with resonances, do not enter into this formalism. For a monochromatic field of frequency u, a constant ionisation rate can then be defined unambiguously and only such continuum states are excited which correspond to the absorption of energy in integral multiples of hu. As an application, differential and total cross sections for the two-photon ionisation of hydrogen, for frequencies below the n = 3 resonance region, are obtained in closed form. Existing data for generalised cross sections, calculated numerically using the complex coordinate method, are in good agreement with the present results. Finally, the mean fractional ionisation resulting from a pulse of finite duration is estimated on the basis of the associated power spectrum. For short pulses, the time dependence of ionisation exhibits a departure from that expected of a time-independent rate.

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