Storage ring measurements of the dissociative recombination of H 3 + : a closer look Holger Kreckel University of Illinois at Urbana-Champaign Kyle N. Crabtree Brian A. Tom Benjamin J. McCall Oldřich 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 TSR Group University of Illinois Richard Thomas Stockholm University Henrik Buhr Weizmann Institute *Columbia University, NY

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look H He CN O Ne Mg Fe SiSAr The relevance of H 3 + : astronomer‘s periodic table

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look The relevance of H 3 + : engine of interstellar chemistry H 3 + formation H 2 + c.r. H e - H H 2 H H Proton-hop reactions H X XH + +H 2

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Steady State: [H 3 + ]  = keke [e - ] [H 2 ] The enigma of H 3 + in diffuse clouds Cosmic ray ionization rate DR rate coefficient

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look year “Perceived” H 3 + DR rate coefficient Glosik et al.( ) Stat. & flow. afterglow Adams, Smith, Alge(1984 ) Flow. afterglow Adams, Smith (1987 ) Flow. afterglow Amano (1988 ) IR spectroscopy Larsson et al. (1993 ) Storage ring McCall et al. (2003 ) Storage ring Kreckel et al. (2005 ) Storage ring Leu, Biondi, Johnsen (1973 ) Stat. afterglow H 3 + DR rate coefficient at 300K

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Storage ring measurements: concept radiative relaxation of internal excitations (rotation, vibration) direct measurement 100% detection efficiency high resolution Advantages Problem H 3 + ! radiative relaxation incomplete

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look (1,0 0 ) theory (2,0 0 ) theory experimental data (T < 1ms) experimental data (T > 2s) (0,0 0 ) theory Coulomb explosion results H 3 + Kreckel et al., PRA 66, (2002) Vibrations decay within the first 2s of storage Some rotational states stay forever

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look H2H2 Gas inlet 2 atm Solenoid valve -900 V ring electrode Pinhole flange/ground electrode H3+H3+ “Cold” ion sources Supersonic expansion CRYRING cm Cryogenic ion trap TSR 2004

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look ● TSR electron temp. kT ┴ =0.5 meV ~ 6K kT || =25 μeV trap temp. 13 K Kreckel, PRL 95, (2005) ● CRYRING kT ┴ = 2 meV ion temp K McCall, Nature 422, 500 (2003) Storage ring results with “cold” H 3 + ion sources Theory Kokoouline and Greene

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look + ortho I = 3/2 para I = 1/2 + The holy grail: state specific measurements H 3 + rotational levels

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Nuclear spin effect: exp. and theory 2005 ۰para H 2 ۰normal H 2 experiment kT ┴ =4 meV theory Greene et al. - para - ortho Kreckel et. al, PRL 95, (2005)

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Theory with more accurate resonance energies S. Fonseca dos Santos et al., JCP 127,

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Quantifying nuclear spin effects B. Tom et al., JCP 130, Reduced rate coeff.

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look skimmer discharge electrode pinhole plunger piezo actuator locking nut 6 cm high pressure H 2 reservoir low pressure Piezo expansion source

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Cavity ring down measurements at UIUC Difference frequency generation: 3.67 μm

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Transitions observed HG

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Rotational temperature pure H 2 discharge, 2bar T rot =110 K 1:5 H 2 :Argon discharge, 2bar T rot =180 K No vibrations found!

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Nuclear spin manipulation 1:5 n-H2 : Argon mixture p-H 3 + fraction p 3 = (47.9 ± 2) % 1:5 p-H2 : Argon mixture p-H 3 + fraction p 3 = (70.8 ± 2) % ortho H 3 + para H 3 +

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look UI Champaign-Urbana MPI-K Heidelberg DR measurements at TSR T est S torage R ing

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Absolute scale of the rate coefficient electron beam switched off electron target length storage ring circumference electron density

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Comparison to CRYRING 2002 CRYRING 2002 (n-H 2 ) TSR 2009 (n-H 2 :Ar 1:5)

1 m DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look H e - beam vel. Rotational temperature: imaging basics d 2-dimensional imaging, point source P(D) 3-dimensional imaging, point source d ~ √E k 2-dimensional imaging, extended source δtδt detector

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look 2-dimensional imaging of the 3-body breakup H e - H + H + H n e (cooler) = 1.4 x 10 7 cm -3 n e (target) = 1.34 x 10 6 cm -3 expected KER = 4.79 eV

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look 2-dimensional imaging of the 3-body breakup 950 K 450 K 200 K rotational temperatures (uncertainties ~ 200 K) H e - H + H + H

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Piezo source extraction potentials

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Conditions on-axis downstream of the nozzle Collisional heating during Ion extraction? skimmer

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Detailed comparison of the (reduced) rate coefficient TSR / 22-pole trap 2007 CRYRING / Solenoid 2002 TSR / piezo 2009

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Nuclear spin dependence of the rate coefficient 1:5 n-H2 : Argon mixture 1:5 p-H2 : Argon mixture p 3 = (47.9 ± 2) % p 3 = (70.8 ± 2) % Extrapolation: 100% ortho H % para H 3 + Reduced rate coeff.

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Summary While we measure a rotational temperature of 200K with CRD spectroscopy, the stored H 3 + 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-H 3 + and para-H 3 + at low energies. The holy grail? Still out there … Results: Kreckel et al., submitted to PRA Petrignani et al., in preparation

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Perspectives: the case to continue the quest Kyle N. Crabtree et al., to be published It is crucial to understand: H H 2 and H 3 + (J=1,K=0,1) + e -

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look Collaboration Kyle N. Crabtree Brian A. Tom Benjamin J. McCall Oldřich 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 TSR Group University of Illinois Richard Thomas Stockholm University Henrik Buhr Weizmann Institute *Columbia University, NY Funding: National Science Foundation Max-Planck Society German-Israeli Foundation Eurppean Comission

DR 2010, Lake Tahoe, Aug 19th 2010 Holger Kreckel Storage ring measurements … of H 3 + : a closer look