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Submillimeter-wave and far-infrared spectroscopy of high-J transitions of ammonia S. Yu, J.C. Pearson, B.J. Drouin and K. Sung Jet Propulsion Laboratory,

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Presentation on theme: "Submillimeter-wave and far-infrared spectroscopy of high-J transitions of ammonia S. Yu, J.C. Pearson, B.J. Drouin and K. Sung Jet Propulsion Laboratory,"— Presentation transcript:

1 Submillimeter-wave and far-infrared spectroscopy of high-J transitions of ammonia S. Yu, J.C. Pearson, B.J. Drouin and K. Sung Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California O. Pirali, M. Vervloet and M.-A. Martin Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, Gif-sur-Yvette, France C.P. Endres I. Physikalisches Institut, Universität zu Köln, Köln, Germany T. Shiraishi, K. Kobayashi and F. Matsushima Department of Physics, University of Toyama, Gofuku, Toyama , Japan Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

2 Hot ammonia in space Shanshan YuHot ammonia Observed at J=18 (E = 3130 K) toward Sgr B2 (Wilson 2006) Expected to exist to larger QN’s in many exoplanets and brown dwarfs Numerous studies on GS and 2 −Summarized in Chen 2006; Reduced RMS = 1 (J≤22) Two global analyses on 2 2 / 4 (5-8 µm) −Sasada 1992, Cottaz 2000; Reduced RMS = 10 (J ≤ 15) One analysis on 2 4 / 1 / 3 (3 µm) −Kleiner 1999; Reduced RMS = 170 (J ≤ 10) NH 3 spectroscopy in lab

3 Project goals – Measure every ammonia terahertz transition the Herschel/HIFI instrument might see (1910–1410 GHz; 1250–480 GHz) – Measure the 4 –2 2 transitions and figure out why the Hamiltonian doesn’t fit the problematic 4 and 2 2 states – Measure the ground state, 2, 2 2, 4 transitions up to extremely high J, with the goal to provide a list of experimental rovibrational energy levels Shanshan YuHot ammonia

4 Summary of NH 3 experiments in this work Shanshan YuHot ammonia 177 terahertz GS and 2 =1 inversion transitions in THz About 2000 far-IR transitions assigned to GS and 2 =1 About 1800 far-IR transitions assigned to 2 2 / 4

5 Extrapolate to zero pressure frequency Shanshan YuHot ammonia 2 (a)– 2 (s)  K  J(J, K)= Q Q(8, 4)

6 Shanshan Yu Global analysis of GS and 2 Hot ammonia

7 Hamiltonian for GS and 2 Shanshan YuHot ammonia Standard rotation-inversion Hamiltonian,  K=3 and 6 sufficient to fit GS and 2 with J up to 35 −4394 transitions and 475 comb. diffs. fitted to 212 parameters −A reduced RMS of 0.9 for all data

8 Summary of rms fit errors (in cm -1 ) Shanshan YuHot ammonia

9 2 (a)– 2 (s)  K  J(J, K)= Q Q (23, 20) from JPL Shanshan YuHot ammonia FWHM = 3.4 MHz

10 FT emission spectrum from Synchrotron SOLEIL Shanshan YuHot ammonia FWHM = ~0.004 cm -1

11 FT absorption spectrum from Synchrotron SOLEIL Shanshan YuHot ammonia N R(3, 3), 2 (a)- 2 (a) p p (7, 4), 2 2 (a) -    a), FWHM = ~0.001 cm -1 Q R(3, 0), 2 (a)- 2 (s) (J’,K’)=(4, 0), 2 (a) Intensity studies: Fabian, 1995 Fabian, 1999 Brown, 1994 Nemtchinov, 2004

12 Intensity problem with  K=3 lines Shanshan YuHot ammonia 0(a)-0(a) (11,1)-(10,2) Q R(12,10), 2 (s)- 2 (a) Q R(10,5), 4 (a), l =-1 to 4 (s), l =-1  K=3 Herman-Wallis terms not included in intensity calculations 0(s)-0(s)

13 Status on 2 2 / transitions constructed (1864 from this work), J<16 RMS = 4 Shanshan YuHot ammonia Pearson et al., OSU, RC02 (Thursday, 8:46 am)

14 Shanshan YuHot ammonia

15 Acknowledgements Shanshan YuHot ammonia Dr. L. Brown Dr. I. Kleiner D. Balcon and the AILES beamline staff NASA Astrophysics Research and Analysis Program (APRA)

16  Herschel-HIFI (Heterodyne Instrument for the Far-IR)  ESA and NASA joint mission  Launch: 2009 (3 years lifetime)  Telescope: 3.5 meter diameter, <100 K temperature  The only space facility dedicated to the terahertz part of the spectrum  Spectral coverage: 151–212 μm (1910–1410 GHz); 240–625 μm (1250–480 GHz)  Objectives: life cycle of gas and dust New terahertz telescopes (I)

17  SOFIA (Stratospheric Observatory For Infrared Astronomy )  NASA and DLR, German Aerospace Center joint mission  Operation: 2010 (20 years lifetime)  The largest airborne observatory in the world  Telescope: 2.5 meter diameter, 240 K temperature  Spectral coverage: 1–700 μm (300000–430 GHz)  Objectives: identification of complex molecules in space, star birth and death etc. New terahertz telescopes (II)

18 New terahertz telescopes (III)  ALMA (Atacama Large Millimeter/Submillimeter Array)  Global collaboration mission: East Asia, Europe, and North America  Location: Chile, 5000 meters above sea level  Operation: 2012 (50 years lifetime)  Telescope: a system up to 66 high-precision dish antennas  Spectral coverage: μm (1000–31 GHz)  Objectives: the physics of the cold Universe

19 Experiments at JPL Shanshan YuHot ammonia H 2 O: 30 mTorr DC discharge: 400 mA, ~3 kV Discharge NH3 Sample cell Pump Beamsplitter Rooftop reflector FM Rf Synthesizer Multiplier chain PC Si detector Lock-in ×6×6 ×2×2 ×3×3 … Source frequency: 400–1230, 1575–1626 GHz Discharge cell: 1.2-meter-long

20 Static quartz cells for stable molecules Shanshan YuHot ammonia Leaking rate: ~1 mTorr/week

21 The 13 rejected microwave lines Shanshan YuHot ammonia


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