Research output: Contribution to journal › Article › peer-review
Photon-mediated charge exchange reactions between 39K atoms and 40Ca+ ions in a hybrid trap. / Li, Hui; Jyothi, S.; Li, Ming; Kłos, Jacek; Petrov, Alexander; Brown, Kenneth R.; Kotochigova, Svetlana.
In: Physical Chemistry Chemical Physics, Vol. 22, No. 19, 21.05.2020, p. 10870-10881.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Photon-mediated charge exchange reactions between 39K atoms and 40Ca+ ions in a hybrid trap
AU - Li, Hui
AU - Jyothi, S.
AU - Li, Ming
AU - Kłos, Jacek
AU - Petrov, Alexander
AU - Brown, Kenneth R.
AU - Kotochigova, Svetlana
PY - 2020/5/21
Y1 - 2020/5/21
N2 - We present experimental evidence of charge exchange between laser-cooled potassium 39K atoms and calcium 40Ca+ ions in a hybrid atom-ion trap and give quantitative theoretical explanations for the observations. The 39K atoms and 40Ca+ ions are held in a magneto-optical (MOT) and a linear Paul trap, respectively. Fluorescence detection and high resolution time of flight mass spectra for both species are used to determine the remaining number of 40Ca+ ions, the increasing number of 39K+ ions, and 39K number density as functions of time. Simultaneous trap operation is guaranteed by alternating periods of MOT and 40Ca+ cooling lights, thus avoiding direct ionization of 39K by the 40Ca+ cooling light. We show that the K-Ca+ charge-exchange rate coefficient increases linearly from zero with 39K number density and the fraction of 40Ca+ ions in the 4p 2P1/2 electronically-excited state. Combined with our theoretical analysis, we conclude that these data can only be explained by a process that starts with a potassium atom in its electronic ground state and a calcium ion in its excited 4p 2P1/2 state producing ground-state 39K+ ions and metastable, neutral Ca (3d4p 3P1) atoms, releasing only 150 cm-1 equivalent relative kinetic energy. Charge-exchange between either ground- or excited-state 39K and ground-state 40Ca+ is negligibly small as no energetically-favorable product states are available. Our experimental and theoretical rate coefficients are in agreement given the uncertainty budgets.
AB - We present experimental evidence of charge exchange between laser-cooled potassium 39K atoms and calcium 40Ca+ ions in a hybrid atom-ion trap and give quantitative theoretical explanations for the observations. The 39K atoms and 40Ca+ ions are held in a magneto-optical (MOT) and a linear Paul trap, respectively. Fluorescence detection and high resolution time of flight mass spectra for both species are used to determine the remaining number of 40Ca+ ions, the increasing number of 39K+ ions, and 39K number density as functions of time. Simultaneous trap operation is guaranteed by alternating periods of MOT and 40Ca+ cooling lights, thus avoiding direct ionization of 39K by the 40Ca+ cooling light. We show that the K-Ca+ charge-exchange rate coefficient increases linearly from zero with 39K number density and the fraction of 40Ca+ ions in the 4p 2P1/2 electronically-excited state. Combined with our theoretical analysis, we conclude that these data can only be explained by a process that starts with a potassium atom in its electronic ground state and a calcium ion in its excited 4p 2P1/2 state producing ground-state 39K+ ions and metastable, neutral Ca (3d4p 3P1) atoms, releasing only 150 cm-1 equivalent relative kinetic energy. Charge-exchange between either ground- or excited-state 39K and ground-state 40Ca+ is negligibly small as no energetically-favorable product states are available. Our experimental and theoretical rate coefficients are in agreement given the uncertainty budgets.
KW - SINGLE
KW - COLLISIONS
UR - http://www.scopus.com/inward/record.url?scp=85085263986&partnerID=8YFLogxK
U2 - 10.1039/d0cp01131b
DO - 10.1039/d0cp01131b
M3 - Article
C2 - 32367082
AN - SCOPUS:85085263986
VL - 22
SP - 10870
EP - 10881
JO - Transactions of the Faraday Society
JF - Transactions of the Faraday Society
SN - 1463-9076
IS - 19
ER -
ID: 62085808