Charge Transfer from the Negative-Energy Continuum: Alternative Mechanism for Pair Production in Relativistic Atomic Collisions

1995 ◽  
Vol 75 (20) ◽  
pp. 3653-3656 ◽  
Author(s):  
Jörg Eichler
Keyword(s):  
Charge Transfer ◽  
Pair Production ◽  
Negative Energy ◽  
Alternative Mechanism ◽  
Atomic Collisions

Impact parameter and semi-classical treatments of atomic collisions

1966 ◽  
Vol 292 (1429) ◽  
pp. 168-179 ◽  
Keyword(s):  
Charge Transfer ◽  
Cross Section ◽  
Impact Parameter ◽  
Expansion Coefficient ◽  
Excitation Cross Section ◽  
Three Dimensional ◽  
Atomic Collisions ◽  
Detailed Consideration ◽  
Usual Manner ◽  
State Approximation

The wavefunction describing the colliding systems being expanded in the usual manner, Ψ(r, R) = SΨ n (r) F n (R) n it is shown that great simplification may be effected by writing F n (R) = μ n (R) F a n (R) where F a n (R) is the three-dimensional J.W.K.B. approximation to the solution of an equation of the form (V 2 + K n (R) 2 ) F n (R) = 0, and where μ n (R) is a modulating function the asymptote to which determines the excitation cross-section. This semi-classical treatment is more accurate than the standard impact parameter treatment. The two treatments are closely related. Indeed if certain additional approximations are made the modulating function μ n (R) of the former becomes identical with the corresponding expansion coefficient a n (R) of the latter. The semi-classical treatment is also applicable when the wavefunction is expanded in terms of the eigenfunctions of the quasimolecule formed by the colliding systems. Detailed consideration is given to the case of symmetrical charge transfer. It is demonstrated that on the two-state approximation the semi-classical treatment, like the full quantal treatment, predicts damping of the oscillations in the probability of charge transfer in close collisions. The four-state approximation is discussed.

scholarly journals Shallow distance-dependent triplet energy migration mediated by endothermic charge-transfer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Runchen Lai ◽  
Yangyi Liu ◽  
Xiao Luo ◽  
Lan Chen ◽  
Yaoyao Han ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Semiconductor Nanocrystals ◽  
Electronic Coupling ◽  
Alternative Mechanism ◽  
Acceptor Pair ◽  
Triplet Energy ◽  
Distance Dependence ◽  
Donor Acceptor ◽  
Triplet Energy Transfer

AbstractConventional wisdom posits that spin-triplet energy transfer (TET) is only operative over short distances because Dexter-type electronic coupling for TET rapidly decreases with increasing donor acceptor separation. While coherent mechanisms such as super-exchange can enhance the magnitude of electronic coupling, they are equally attenuated with distance. Here, we report endothermic charge-transfer-mediated TET as an alternative mechanism featuring shallow distance-dependence and experimentally demonstrated it using a linked nanocrystal-polyacene donor acceptor pair. Donor-acceptor electronic coupling is quantitatively controlled through wavefunction leakage out of the core/shell semiconductor nanocrystals, while the charge/energy transfer driving force is conserved. Attenuation of the TET rate as a function of shell thickness clearly follows the trend of hole probability density on nanocrystal surfaces rather than the product of electron and hole densities, consistent with endothermic hole-transfer-mediated TET. The shallow distance-dependence afforded by this mechanism enables efficient TET across distances well beyond the nominal range of Dexter or super-exchange paradigms.

Laser-assisted symmetric charge transfer in atomic collisions

1981 ◽  
Vol 14 (20) ◽  
pp. 3961-3976 ◽  
Author(s):  
G Ferrante ◽  
L Lo Casico ◽  
B Spagnolo
Keyword(s):  
Charge Transfer ◽  
Atomic Collisions
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