Storage ring measurements of the

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Storage ring measurements of the Dissociative
Recombination of H3 a closer look
Holger Kreckel University of Illinois at
Urbana-Champaign
studied in the laboratory.
A fundamental process in space .
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Dissociative recombination of molecular ions
AB e- A B
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Brief History of Dissociative Recombination (DR)
Solar radiation produces a lot of electrons in
the Ionosphere by photoionization. How are these
electrons removed?
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Dissociative recombination of molecular ions
Bates, D.R., Dissociative Recombination, Phys.
Rev. 78, 492 (1950)
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Importance of DR in the interstellar medium
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
The Problem with H3 DR (experiment)
H2H HHH
H3e-
DR rate coefficient
upper limits
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
The Problem with H3 DR (experiment)
H2H HHH
H3e-
DR rate coefficient
upper limits
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Storage ring measurements concept
Advantages
radiative relaxation of internal excitations
(rotation, vibration)

• direct measurement

• 100 detection efficiency

• high resolution

Problem
H3
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Rotationally cold ion sources
Gas inlet 2 atm
H2
Solenoid valve
CRYRING 2002
Supersonic expansion
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Storage ring results with cold H3 ion sources
? TSR electron temp. kT-0.5 meV 6K kT25
µeV trap temp. 13 K Kreckel, PRL 95, 263201
(2005)
? CRYRING kT- 2 meV ion temp. 30-50 K McCall,
Nature 422, 500 (2003)
Theory Kokoouline and Greene
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
The holy grail state specific measurements
para I 1/2
ortho I 3/2
H3 rotational levels
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Nuclear spin effect exp. and theory 2005
?para H2 ?normal H2
experiment kT-4 meV
theory Greene et al.
- para - ortho
Kreckel et. al, PRL 95, 263201 (2005)
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Theory with more accurate resonance energies
S. Fonseca dos Santos et al., JCP 127, 124309
2007
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Piezo expansion source
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Rotational temperature of H3 inferred from
cavity ring-down spectroscopy of the ion source
pure H2 discharge, 2bar
Trot110 K
15 H2Argon discharge, 2bar
Trot180 K
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Nuclear spin manipulation
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DR 2010, Lake Tahoe, Aug19th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
DR measurements at TSR
UI Champaign-Urbana
MPI-K Heidelberg
Test Storage Ring
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Comparison to CRYRING 2002
TSR 2009 (n-H2Ar 15)
CRYRING 2002 (n-H2)
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
2-dimensional imaging of the 3-body breakup
H3 e- H H H
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
2-dimensional imaging of the 3-body breakup
H3 e- H H H
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Conditions on-axis downstream of the nozzle
Collisional heating during Ion extraction?
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Nuclear spin dependence of the rate coefficient
p3 (47.9 2)
15 n-H2 Argon mixture
p3 (70.8 2)
15 p-H2 Argon mixture
Extrapolation 100 ortho H3 100 para H3
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Summary
While we measure a rotational temperature of
200K with CRD spectroscopy, the stored H3 ions
are much hotter than the ion source.
We observed clear differences between different
ion sources ? the heating is probably happening
prior to injection into the ring .
We observed for the first time detailed
structures in the rate coefficients for
ortho-H3 and para-H3 at low energies.
Results Kreckel et al., 82, 042715
(2010) Petrignani et al., in preparation
The holy grail?
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Collaboration
TSR Group
University of Illinois
Kyle N. Crabtree Brian A. Tom Benjamin J. McCall
Oldrich Novotny Annemieke Petrignani Max H.
Berg Dennis Bing Manfred Grieser Claude
Krantz Michael Lestinsky Mario B.
Mendes Christian Nordhorn Roland Repnow Julia
Stützel Andreas Wolf
Weizmann Institute
Henrik Buhr
Stockholm University
Richard Thomas
Columbia University, NY
German-Israeli Foundation
National Science Foundation
Max-Planck Society
Funding
Eurppean Comission
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MWAM 2010, Nov6th 2010 Holger Kreckel
Storage ring measurements of H3 a closer look
Perspectives the case to continue the quest
It is crucial to understand H3 H2 and H3
(J1,K0,1) e-
Next speaker Kyle Crabtree