1. 1 Infrared Spectroscopy of Ammonium Ion MG03: Sub-Doppler Spectroscopy of ND 3 H + Ions in the NH Stretch Mode MG04: Infrared Spectroscopy of Jet-cooled ND 2 H 2 + Molecular Ions: The Symmetric and Antisymmetric NH Stretch Modes The Symmetric and Antisymmetric NH Stretch Modes CHIH-HSUAN CHANG, Grant Buckingham, and David J. Nesbitt JILA, NIST, University of Colorado Department of Chemistry and Biochemistry, University of Colorado at Boulder Boulder, CO 80309 International Symposium on Molecular Spectroscopy 68 th meeting, Jun17-21, 2013, OH

2. 2 Introduction NH 4 + ion is a crucial species in acid-base chemistry and aqueous solution Carrier of spectra in the Young Stellar Objects (YSO)

3. 3 Located approximately 12,000 light-years away from Earth, in the constellation SagittariusAstronomy Gibb et. al. The Astrophysical J. 536,347(2000) W. A. Schutte and R. K. Khanna, A&A, 398, 1049(2003) NH 4 +

4. 4 H3+H3+ H3O+H3O+ OD 3 + HOD 2 + H 2 OD + Isotope-substituted Ion Species NH 2 D 2 + NH 4 + NHD 3 + ND 4 + Symmetry reduction results in the multiple non-degenerate vibrations and intensity dilution

5. 5 Fundamental Vibration Modes Jacox and Thompson, PCCP, (7) 765, 2005 Intensity in unit of km/mol. Oka group Saykally group Oka group Saykally group Nakanaga and Amano Park et. al.(1996)

6. 6 Frequency calibration  Polarization-stabilized HeNe laser Laser scanning  Fabry-Perot interferometer Concatenation  Marker cavity Sub-Doppler Resolution Infrared Spectrometer

7. Absorption noise level ~ 1.3  10 -3 % Absorbance ~ 0.055 % Signal to noise ratio ~ 45 Sub-Doppler resolution ~ 120 MHz (H 2 gas) Chemical reaction route : H 2 + e -  H 2 + + 2e - H 2 + + H 2  H 3 + + H H 3 + + ND 3  ND 3 H + + H 2 H 3 + + ND 2 H  ND 2 H 2 + + H 2 Discharge Slit-jet General Advantages:  Sub-Doppler resolution (60 MHz)  Rotational cooling (15 K)  High density of radicals or cation. mirror Slit jet

8. 8 Band Type Structure of Transition bb cc  // 1 6 1 Oblate Top (A = B > C) Asymmetric Top(  =  0.27)

9. 9 Nuclear Spin Statistics ND 3 H + ionK  Rot g ns 0 J even A1A1A1A111 J odd A2A2A2A211 3n±1 E16 3n±3 A 1 + A 2 22 g ns K a + K c = even 15 K a + K c = odd 21  (e)  (v)  (r)  (ns)  (total) a1a1a1a1 a1a1a1a1 a1a1a1a1 b2b2b2b2 b 1 or b 2 a1a1a1a1 a1a1a1a1 b1b1b1b1 a1a1a1a1 a1a1a1a1 a1a1a1a1 b2b2b2b2 a1a1a1a1 a1a1a1a1 a1a1a1a1 a2a2a2a2 b2b2b2b2 ND 2 H 2 + ion

10. 10 Global View Region of NH Modes ND 2 H 2 + Symmetric mode( 1 ) ND 2 H 2 + Antisymmetric mode ( 6 ) ND 3 H + NH stretch mode( 1 ) NDH 3 + Asymmetric mode ( 4 )

11. 11 Stick Plot of Rotational Structure ND 2 H 2 + Antisymmetric mode (v 6 ) ND 2 H 2 + Symmetric mode( 1 ) ND 3 H + NH stretch mode( 1 ) NDH 3 + Asymmetric stretch mode( 4 )

12. 12 Results of ND 3 H + Ion

13. 13 Q branch feature of parallel band Ground state combination difference (GSCD) Nuclear spin statistic Some transitions show perturbation High Resolution Jet-cooled Spectrum

14. 14 Boltzmann Plot and Rotational Temperature Expected value 22 K=3 16 K=1, 2 11 K=0 ND 3 H +

15. 15 Fitting Results: B”3.706595(26) C”2.9069 D” J 6.71(25)  10 -5 D” JK  6.70(68)  10 -5 D” K 0  // 1 F(J,K)=BJ(J+1)+[C-B]K 2  D J J 4  D JK J(J+1)K 2  D K K 4B’3.65114(76)C’2.90102(48) D’ J 2.893(62)  10 -3 D’ JK  2.360(14)  10 -3 D’ K  7.15(92)  10 4 03316.8347(19)

16. 16 Results of ND 2 H 2 + Ion cc bb

17. 17 Jet-cooled Spectrum of v 6 Mode ND 2 H 2 +

18. 18 Jet-cooled Spectrum of v 1 Mode ND 2 H 2 +

19. 19 Band Intensity for v 6 and v 1 Modes Bond-dipole model  I(Q antisym ) / I(Q sym ) = 2/1

20. 20 Ground 1 mode 1 mode 6 mode 6 mode A4.85675(5)4.80782(4)4.82922(4) B3.96819(4)3.94615(6)3.94784(3) C3.44667(5)3.44190(5)3.43182(5)  J  10 6 6.5(1.6)13.0(1.2)4.2(1.5)  K  10 6 5.3(9.4)20.7(12.4)1.5(7.4)  J  10 5 6.5(3)6.3(2)6.2(2)  JK  10 5  4.8(9)  4.3(8)  3.6(9)  K  10 4 1.18(9)0.90(6)1.34(6) v0v0v0v03297.5439(1)3337.9050(1) Fitting Results of ND 2 H 2 + Ion A-reduced Hamiltonian ~ 40 cm -1

21. 21 Theoretical Calculation ND 2 H 2 + ND 3 H + Exp.Cal.Exp.Cal. 13297.5439(1)3297.6-0.0563316.834(1)3311.45.434 2 3 4 5 63337.9050(1)3333.44.505 7 8 9 Chem. Phys. Lett, 258, 129(1996)

22. 22 Jet-cooled Spectrum of NDH 3 + ion NDH 3 +

23. 23 Q branch of 4 (E) Mode T. Nakanaga, T. Amano, Can. J. Phys., 64, 1356 (1986) Vibration angular momentum l-type doubling

24. Summary High resolution of jet-cooled spectra of NH stretch modes of ND 3 H + ( 1 ) and ND 2 H 2 + ( 1, 6 ) assigned for the first time Band origins and band types are determined Band intensity of v 1 and v 6 mode and bond dipole physical model Fingerprint in astronomy N2H7+N2H7+ H 5 O 2 + (Zundel or Eigen) ? Further work will be extended into hydrogen bonded complexes

25. 25 Acknowledgement David J. Nesbitt Grant Buckingham Melanie Roberts (Stony Brook) Thank you for your attention JILA