1. Millimeter- Wave Spectroscopy of Hydrazoic acid (HN 3 ) Brent K. Amberger, Brian J. Esselman, R. Claude Woods, Robert J. McMahon University of Wisconsin June 18, 2014

2. Previous Work on HN 3 Kewley, R.; Sastry, K. V. L. N.; Winnewisser, M., Journal of Molecular Spectroscopy 1964, 12, 387-401. Bendtsen, J.; Winnewisser, M., Chemical Physics Letters 1975, 33, 141-145. Bendtsen, J.; Winnewisser, M., Chemical Physics 1979, 40, 359-365. Herzberg, G.; Patat, F.; Verleger, H., Z. Elektrochem. Angew. Phys. Chem. 1935, 41, 522-4. 1930’s 1960’s- 1970’s 1980’s- 1990’s Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1986, 118, 12. Hegelund, F.; Bendtsen, J., Journal of Molecular Spectroscopy 1987, 124, 306-316. Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1988, 128, 309-320. Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1991, 145, 123-129. Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1992, 152, 101-108. Bendtsen, J.; Guelachvili, G., Journal of Molecular Spectroscopy 1994, 165, 159-167. Hansen, C. S.; Bendtsen, J.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1996, 175, 239-245.

3. The Synthesis Dry Ice Trap To Spectrometer H 2 O or D 2 O NaN 3 or Na 15 NNN Access to: HNNN DNNN H 15 NNN / HNN 15 N D 15 NNN / DNN 15 N

4. Our Spectrometer ~260-360 GHz range 20 mTorr sample Room temperature

5. CCSD(T)/ANO2 Structure 1.017 Å 108.71 ° 171.65° 1.132 Å 1.244 Å a b

6. Predicted Spectra for HN 3 and DN 3 HN 3 DN 3 Our Range

7. K=2 K=0 K=3 K=4 K=5 K=6 K=7 K=1 R- Series Anatomy HN 3 J = 13  12

8. The Spectrum: Full Range 235-360 GHz J = 14  13 J = 15  14 J = 13  12 J = 11  10 J = 12  11 J = 10  9

9. The Spectrum: Key Features HN 3 J = 13  12 H 15 NNN J = 13  12 HNN 15 N J = 13  12 K=1 K=0 Vibrationally excited modes 35 0 35  34 1 34 11 1 11  12 0 12

10. The Spectrum: H 15 NNN K=0 K=2 K=3 K=4 K=5 H 15 NNN at natural isotopic abundance J = 13  12

11. Finding Naturally Occurring Center 15 N Loomis- Wood plots centered on H 14 N 3 lines were used to find corresponding HN 15 NN lines

12. The fit data: HN 3 Bendtsen and Winnewisser 1975 (MHz) Present Work (MHz) CCSD(T)/ANO2 (MHz) A610996.2 (6.0)610766.49 (46)605072 B12034.1465(50)12034.951(47)11989 C11781.4512(50)11780.700(48)11737 DJDJ 0.004673(35)0.0049185(33)0.00475 D JK 0.7911858(11)0.79676(21)0.904 DKDK [230][0]224 djdj 0.0000888(27)0.00009045(54)0.0000769 dkdk [0]0.388(23)0.379 HJHJ 0.000000088(36)-0.0000000037(13) H JK 0.0000406(86)0.00000144(17) H KJ -0.001210(35)0.000135(20) HKHK [0] L KKJ -0.00003712(55) Bendtsen, J.; Winnewisser, M., Chemical Physics Letters 1975, 33, 141-145.

13. Summary of Isotopologues HNNNH 15 NNNHN 15 NNHNN 15 NH 15 N 15 NNH 15 NN 15 NHN 15 N 15 N A (MHz) 610766.491(46)605313.25(68)609767.695(52)610709.650(89)601081.(730)603383.(332)? B (MHz) 12034.951(47)11668.9(11)12034.147(21)11642.534(49)11666.735(83)11283.234(42)? C (MHz) 11780.700(48)11426.4(11)11779.488(21)11404.322(49)11424.417(81)11057.174(41)? n 11074586245614? DNNND 15 NNNDN 15 NNDNN 15 ND 15 N 15 NND 15 NN 15 NDN 15 N 15 N A (MHz) 344746.666(24)340247.371(21)344527.615(51)344727.850(25)340007.070(18)340145.581(18)344511.062(32) B (MHz) 11350.9654(26)11045.7287(31)11347.9000(67)10980.1221(31)11042.005(11)10680.229(13)10979.119(19) C (MHz) 10964.8155(27)10675.2595(25)10963.1789(67)10618.3330(27)10671.754(12)10333.591(13)10617.349(18) n 16213686134678357 Cannot access H 15 N 15 N 15 N or D 15 N 15 N 15 N

14. R e Structure Determination Experimental constants were corrected for vibration- rotation interaction and electron mass. Using xrefit module in CFOUR: Fit 5 structural parameters to 39 moments of inertia. 1.01559(63) Å 1.2438(14) Å 1.1290(15) Å 108.976(64)° 171.14(19)° b a

15. Structure Comparison CCSD(T)/ANO2 (R e ) xrefit (R e )Substitution Structure (R s ) R 1 (Å)1.1331.1290(15)1.159(50) R 2 (Å)1.2451.2438(14)1.204(61) R 3 (Å)1.0171.01559(63)1.017(12) A1A1 108.71°108.976°(64)108.0°(21) A2A2 171.65°171.14°(19)171.26°(57) R3R3 R2R2 R1R1 A1A1 A2A2

16. Excited Vibrational States HN 3 DN 3 Ground ν5ν5 ν6ν6 ν4ν4 2ν52ν5 2ν62ν6 ν 5 + ν 6 ν3ν3 0 cm -1 537.25 cm -1 606.36 cm -1 1147.40 cm -1 1266.63 cm -1 ~1143.5 cm -1 ~1213 cm -1 ~1074 cm -1 954.77 cm -1 0 cm -1 495.74 cm -1 586.49 cm -1 ~991 cm -1 ~1082 cm -1 1197.39 cm -1 1162.42 cm -1 Ground ν5ν5 ν6ν6 ν4ν4 2ν52ν5 2ν62ν6 ν 5 + ν 6 ν3ν3 Coriolis perturbation Centrifugal distortion perturbation

17. Past IR Work -A large body of work analyzing each rotationally-resolved band in HN 3 and DN 3 IR spectra has been published. -Rotational constants and coupling terms from IR data has been published. -Published data does not adequately predict lines for vibrationally excited states in our millimeter-wave spectra. -The published data is still an outstanding starting point for our own analysis. Hegelund, F.; Bendtsen, J., Journal of Molecular Spectroscopy 1987, 124, 306-316. Bendtsen, J.; Hegelund, F.; Nicolaisen, F. M., Journal of Molecular Spectroscopy 1988, 128, 309-320. For our analysis of ν 5 and ν 6 the literature gives us starting points for the rotational constants and 3 separate Coriolis terms: Z a, η bc and Z b. Also provides very accurate energy separation between states. The published high-resolution rovibrational transitions allow us to calculate where the pure rotational transitions should be.

18. Finding HN 3 ν 5 13 3 10 – 12 3 9 ν 5 Ground 13 3 10 12 3 9 13 3 10 11 3 8 13 3 10 14 3 11 Calculated from R- branch IR transitionsCalculated from P- branch IR transitions 309933 MHz309937 MHz Error of 0.001 cm -1 = 30 MHz

19. Initial Assignments of ν 5 and ν 6 Lines Calculated from P-branch IR transitions Calculated from R-branch IR transitions

20. Initial Assignments of ν 5 and ν 6 Lines Lines assigned based on rovibrational transitions

21. Fit for States ν 5 and ν 6 of HN 3 Actual Fit!

22. Combined fit for ν 5 and ν 6 of HN 3 ν5ν5 Present WorkHegelund et al. 1987 A675700 (2800)590240(19) B12073.79 (30)12061.76(66) C11778.56 (30)11790.63(66) ν6ν6 Present WorkHegelund et al. 1987 A739181(3458)623487(19) B12039.160(271)12029.44(66) C11797.462(271)11807.30(66) Present WorkHegelund et al. 1987 ZaZa 1.2434(32)*10 6 [1.141*10 6 ] η bc 9.30 (19)9.65(24) ZbZb 1828.2 (30)1874.3(39) E[2071299]

23. Combined fit for ν 5 and ν 6 of DN 3 ν5ν5 Present WorkHegelund et al 1987 A340411.947(17)327613(12) B11387.10792(11)11386.33(57) C1097.530533(97)10971.95(57) ν6ν6 CurrentHegelund et al 1987 A342198.19 (14)361742(36) B11350.58853 (84)11348.31(57) C10985.59915 (66)10987.36(57) Present WorkHegelund et al 1987 ZaZa 595173.573(42)[565409] η bc 4.62773(12)4.80(90) ZbZb 1382.399(79)2130(180) E[2720661.5]

24. Summary and Ongoing Work Best structure of HN 3 to date. 1.01559(63) Å 1.2438(14) Å 1.1290(15) Å 108.976(64)° 171.14(19)° Find more lines, especially B-type lines to tighten up the fits. Accomplished: In Progress: Combined fits for Coriolis coupled ν 5 and ν 6 states. Investigate the complex coupling patterns of the higher energy vibrationally excited states.

25. Thanks for Listening! McMahon group + R.C. Woods