Dr. Annemieke Petrignani MPI for Nuclear Physics, Heidelberg

1. Visible transitions from ground-state H3+and their Einstein-B coefficients measured with high-sensitivity action spectroscopy Dr. Annemieke Petrignani MPI for Nuclear Physics, Heidelberg (Current affiliation: Leiden Observatory) Royal Society Discussion Meeting Chemistry, astronomy and physics of H3+ 9-10 February 2012

2. Outline • Introduction • Action spectroscopy on Cold H3+ in a 22-pole ion trap • Visible Transitions of H3+ • Transition Frequencies • Einstein B coefficients • Conclusions & Discussion

3. R r IntroductionTheory     Horseshoe States almost no exp data exp well studied Einstein A Coefficients Band Origins (cm-1) Munro et al., Mol. Phys. 104 (2006) 115

4. IntroductionTheory & Experiment … previously T. Oka and co., Absorption Spectroscopy Population distributed over many J (overtones and hot bands) High H3 Rydberg background Gottfried et al. 2006 Laboratory Oka & co: [1] Gottfried et al. 2003 [2] Gottfried et al. 2006 [3] Morong et al. 2009 Sensitivity limit reached Theory SAH (Schiffels, Alijah, Hinze) 2003 corrected using [1]

5. Action Spectroscopy on Cold H3+in a 22-pole ion trap H3+ H2 55 K H3+(v<2) + Ar ArH+ + H2 ArH+ + H2 H3+(v≥2) + Ar Laser Ar He buffer gas reactant gas

6. Action Spectroscopy on Cold H3+in a 22-pole ion trap + + Ar H3+ H3+ H3+ H3+ ArH+ ArH+ H2 H2 Signal laser-induced ArH+ BG non laser-induced ArH+ H3+ H3+ H3+ 55 K Laser Ar He buffer gas reactant gas

7. Action Spectroscopy on Cold H3+in a 22-pole ion trap H3+ ArH+ H2 Signal laser-induced ArH+ BG non laser-induced ArH+ high P[H2] scintillator + Al PMT + filter • background sources • photons (minimal) • ambient • laser (λ dependent) • ArH+ • initial H3+ • ArH+ lifetime differential pumping 55 K Laser low P[H2]

8. Action Spectroscopy on Cold H3+in a 22-pole ion trap Exp – T1 T2 T3 NMT96 SAH03 SAH03c (AA10) (JT pc) J=1-2 1014 1019 1013 Theory – Exp – unknown T1 T3 T2 M.H. Berg, PhD Thesis, 2011 A. Petrignani et al. 2009 1.6 predictions of Schiffels, Alijah, Hinze, 2003 Neale, Miller, Tennyson, 1996 aid search, choose observable transitions & give assignments Theory – 1017 1017 1017 search window up to 10 cm-1!!!

9. Transition FrequenciesPreviously… <13,700 cm-1 • TiSa laser • 103 H3+ ions • 10-4/5 x fundamental B0001 • 0.01 cm-1 absolute resolution • 0.001 cm-1 relative resolution • 23 Transitions frequencies • 17 new, 6 known • In agreement with Gottfried 2003 [4] Kreckel et al., JCP 129 (2008) 164312 [5] M. Pavanello et al., Phys. Rev. Lett. 108 (2012) 023002

10. Transition Frequencies>15,000 cm-1 • TiSa & Dye laser (DCM & Rh. B) • 104-105 H3+ ions • 10-6 x fundamental B0001 • 0.005 cm-1 absolute resolution • <0.001 cm-1 relative resolution • 3 weak transitions <13,700 cm-1 • 7 transitions >15,000 cm-1 [4] Kreckel et al., JCP 129 (2008) 164312 [5] M. Pavanello et al., Phys. Rev. Lett. 108 (2012) 023002

11. Transition FrequenciesTheory & Experiment… updated Theory NMT: Neale, Miller, Tennyson, 1996 SAH: Schiffels, Alijah, Hinze 2003 unscaled 2003 scaled using [1] Alijah J. Mol. Spectrosc. 264 (2010) 111 using [1-5] Laboratory Oka & co: [1] Gottfried et al. 2003 <13,700 cm-1 [2] Gottfried et al. 2006 [3] Morong et al. 2009 MPI: [4] Kreckel et al. 2008 <17,000 cm-1 [5] M. Pavanello et al. 2012 total 35 transition frequencies from J=1

12. Transition FrequenciesTheory & Experiment… latest status! BO+DA+REL average deviation of 0.1 cm-1! BO+DA M. Pavanello et al. Phys. Rev. Lett. 108 (2012) 023002 BO Born-Oppenheimer approximation DA Diagonal Adiabatic correction REL Relativistic effect

13. B12·NH3+·PL·A·[1-exp(-tLIT/A)] ·T NArH+ Einstein B Coefficientsmeasuring line intensities 105 10-1/100 J=1-2 VIS: ~10-6 x fundamental • Relative Normalisation • Constant conditions • Dynamic count range • Absolute Normalisation • Reference line (0,00)  (0,31) • “Known” Einstein B coefficient • Measured for every transition

14. Einstein B CoefficientsTheory & Experiment Munro et al., Mol. Phys. 104 (2006) 115

15. Einstein B CoefficientsTheory & Experiment

16. Conclusions & Discussion • Observation of ro-vibrational levels • up to 17,200 cm-1 (dissociation ~35,000 cm-1) • 35 frequencies, 18 probabilities • Good agreement with theory • Resolution • Relative <0.001 cm-1 • Absolute ~0.005 cm-1 (calibration to Li lines)

17. Conclusions & Discussion • Extend spectroscopy to above 17,000 cm-1 • Use Neon or Helium as probe gasses • lower background, lower T • Improve sensitivity • lower photon background (timing) • lower non-laser induced ArH+ (pulsed valve) • increase H3+ • Use improved predictions <0.3 cm-1 (10 cm-1 deviation gives ~10 day search) • Prediction-independent search • Sensitivity increased by 102 • Transitions intensities down to Bij~1017 cm3/Js2 • Sensitivity limit not reached yet

18. Max Berg Dennis Bing Florian Grussie Holger Kreckel Andreas Wolf Acknowledgements Sascha Reinhardt – currently at MPI für Quantenoptik, Germany AP – currently at Leiden Observatory, NL Many thanks to Jonathan Tennyson and co-workers, UCL, UK Alexander Alijah, Reims University, France

19. Thank you for your attention