An Investigation of Charge Transfer and Ionization in Li+ Colliding with Na Atom Collisions Embedded in Classical and Dense Quantum Plasmas
Mukesh Kumar Pandey1,2*, Y. –C. Lin2, Y. K. Ho2
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
* presenting author:Mukesh Kumar Pandey, email:pandey@pub.iams.sinica.edu.tw
Several studies on collision between alkali ions and atoms have been carried out in last few decades. However, most of them cover collisions in high energy range and plasma-free conditions [1 and references therein]. In fact, in last few decades atomic collision processes embedded in plasma environments has attracted great attention of many atomic and molecular physicists[2 and references therein]. Once plasma environments applied to the studied system, these studies prove very useful for diagnosing the density of laboratory cold plasmas. In the present study we explored the cross section behaviors of charge exchange and ionization in the collision of Li+ + Na artom with energy ranged from 1 to 500 keV/u with two type of plasma environments, i.e., weekly coupled plasmas (WC Plasmas) or classical plasmas and dense quantum plasma (DQ Plasmas) or quantum plasmas. In classical plasmas, electron–ion interaction is described by the Debye Hückel potential or static screened Coulomb potential (SSCP)
VSSCP=-(1/r)*exp(-r/rd).....................(1)
In quantum plasmas, electron–ion interaction is described by the exponential cosine screened potential (ECSCP), which can be expressed as,
VECSCP=-(1/r)*exp(-r/rd)*cos(-r/rd).....................(2)
where 1/rd is screening parameter and it is related to the plasma temperature (Te) and density (ne) by rd =(KBTe/4πe2ne)1/2, where rd is called the Debye length, KB is the Boltzmann constant, and e is the electronic charge.
Our result are in good agreement with the existing theoretical predictions in plasmas free environments. It is found that charge exchange cross sections at all the screening parameter are always low and ionization cross sections are always high for both plasma conditions compared with the plasma-free condition. In fact, in week screen conditions, charge exchange and ionization cross sections in both WC and DQ plasmas are approximately the same. However, in strong screening conditions, both charge exchange and ionization cross sections are significantly changed in WC plasma and the change become more effective with decrease in Debye length rd. Detail results will be presented at the meeting.

This work was supported by the Ministry of Science and Technology (MOST) of Taiwan.

References:
1. L. L. Yan, et al., Phys. Rev. A 88 012709 (2013) .
2. M. K. Pandey et al., Phys. of Plasmas 22, (2015) 052104


Keywords: Quantum plasma , Debye Hückel potential , exponential cosine screened potential (ECSCP), Atomic collisions, Charge exchange