Summary
Total resonant charge transfer cross-sections are calculated for the Rb++Rb→Rb+Rb+ reaction by using an atomic two-state picture within the impact parameter formalism and a model potential approach. Different model potential simulations of the alkali atom are used. In two cases the calculated total cross-sections exhibit an oscillatory structure, while in the other two cases no oscillation is present. It shows that the results are critically dependent upon the alkali atom treatment. An effort is made to correlate the behaviour and the absolute values of the cross-sections to the peculiarities of the different model potential simulations. In particular, it is suggested that the oscillatory behaviour is exhibited by the cross-sections only when the model potential and the model wave function give rise to a barrier along the line joining the two alkali cores not too high nor too large at small internuclear distances such as to allow the valence electron to undergo a process of alternate tunnelling. Furthermore, it is shown that again the model potentials and the model wave functions affect the absolute value of the cross-sections through the tail of the gerade potential.
Riassunto
Si calcolano sezioni d'urto totali di trasferimento di carica risonante per la reazione Rb++Rb→Rb++Rb, usando un modello atomico a due stati nell'ambito del formalismo del parametro d'impatto e un approccio di potenziale modello. In due casi le sezioni d'urto totali mostrano una struttura oscillante, mentre in altri due non è presente nessuna oscillazione. Si mostra che i risultati dipendono in modo critico dal trattamento dell'atomo alcalino. Si fa un tentativo di correlare il comportamento e i valori assoluti delle sezioni d'urto con le peculiarità delle diverse simulazioni dell'atomo alcalino mediante potenziale modello. In particolare, si ritiene che le oscillazioni siano presenti nelle sezioni d'urto solo quando la funzione d'onda e il potenziale modello danno origine ad una barriera lungo la linea congiungente i due noccioli alcalini non troppo alta e non troppo larga a piccole distanze internucleari da non impedire all'elettrone di valenza di compiere un processo di tunneling alternato. Inoltre si mostra che il potenziale e la funzione d'onda modello controllano anche il valore assoluto della sezione d'urto attraverso la coda del potenziale gerade.
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Ferrante, G., Cascio, L.L. & Leone, C. Model potential simulations and charge transfer cross-sections. Nuov Cim B 51, 91–103 (1979). https://doi.org/10.1007/BF02743699
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DOI: https://doi.org/10.1007/BF02743699