THE MICROWAVE SPECTROSCOPY OF AMINOACETONITRILE IN THE VIBRATIONAL EXCITED STATES 2 (Toho Univ.a, Univ. Toyamab) Chiho Fujitaa, Haruka Higurashia, Hiroyuki Ozekia, and Kaori Kobayashib 2016 Jun 21st International Symposium on Molecular Spectroscopy, Illinois

Road to Glycine Glycine Gas Phase Rxn. Dust Surface Rxn. Strecker Rxn. CH3NH2 Gas Phase Rxn. Dust Surface Rxn. Strecker Rxn. Gas-Dust Rxn. Others

Motivation: Origin of Life Search for Glycine in Interstellar cloud Amino acid Glycine (NH2CH2COOH) Alanine, Glutamine, etc… Life Protein Example of Previous Attempts to Search for Glycine Freq.(GHz) Sources Detected ? Brown et al. (1979) 23 - 83 Sgr B2, Ori A, etc. × Hollis et al. (1980) 80 - 100 Sgr B2 Combes et al. (1996) 101 - 223 Sgr B2, Orion Ceccarelli et al. (2000) 101, 216 IRAS 16293 - 2422 Kuan et al. （2003） 79 - 251 Sgr B2, Ori KL, W51 e1/e2 ？ Etc. I’d like to introduce origin of life, amino acid shortly. Our life is consist of protein, similarly protein consists of amino acid. So usually glycine has been used to explore amino acid in interstellar regions. This table is example of previous search for glycine. Until Kuan et al. (2003) there were no reports to detect glycine.

Synthesis of amino acid via Strecker Reaction Strecker Syntheses (Strecker (1850)) One of the famous reactions that produce amino acid in laboratory. H2O Methaneimine CH2NH Aminoacetonitrile NH2CH2CN Glycine NH2CH2COOH HCN H2CO NH3 + In this study, we focused this generating pathway, Strecker reaction. This is the one of the famous reaction that produce amino acid in the lab frame. In this reaction, AAN is the precursor of glycine.

Structure of AAN AAN NC 1.4760Å CC’ 1.4611Å C’N’ 1.1594Å CH 1.0940Å NH 1.0138Å NCC’ 114.54° HCH 102.4° HNC 109.6° HNH 107.3° CC’N’ 180.0° Hydrogen Carbon Nitrogen N N’ C C’ This is the structure of AAN. Pickett (1973)

Previous Pure Rotational Studies of AAN in the Ground State MacDonald & Tyler 1972 Measured AAN spectra in the microwave region. a-type: 3 lines b-type: 2 lines Pickett 1973 Measured AAN and its deuterated isotopologues (NHD-, ND2-) spectra in microwave region. Determined electric dipole moment. 　　　　　μa =2.577(7)D, μb =0.5754(10)D Brown et al. 1977 Determined hyper fine coupling constant of nitrogen nuclei. Bogey et al. 1990 Measured AAN spectra in the millimeter wave region. 　　J’ ≤ 40 a-type: 110 lines, b-type: 5 lines. Belloche et al. 2008 Reanalysis of the previous data. Motoki et al. 2013 Extension to the Terahertz region. Corrected assignment of the b-type transitions J’ ≤ 40 a-type: 110 lines, b-type: 5 lines. This table is previous studies of AAN. First, MacDonald & Tyler measured AAN spectra in microwave region. Next, Pickett measured AAN and its deuterated isotopologues (NHD-, ND2-) spectra in microwave region, and decided electric dipole moment. μa =2.577(7)D, μb =0.5754(10)D. Dipole of a-axis is about five times larger than that of b-axis. Next, Brown et al. determined hyper fine coupling constant of Nitrogen nuclei. Green letter is amino nitrogen’s hyper fine coupling constant. Blue letter is nitrile nitrogen’s one. The last, Bogey et al. measured AAN spectra in millimeter wave region, and determined molecule constant.

Detection of AAN towards Sgr B2(N) Belloche et al. (2008) succeeded to detect AAN’s millimeter wave spectra towards Sgr B2(N)!! Detected region 80~260GHz Detected line 51 a-type transitions GHz After that, with this revised molecular constant, Belloche et al. (2008) succeeded to detect AAN’s millimeter wave spectra towards Sgr B2(N)!! This figure is example of detected line. The vertical axis is main beam temperature, horizontal axis is frequency. The red line is shows AAN’s spectra line. CDMS

Low-lying Vibrational Excited States Observed Frequency (cm-1) a Ab Initio Frequency (cm-1) b Mode Description 558 563 NCC bending 370 379 NH2-CH2 torsion 247 265 NH2 torsion 235 208 CCN bending According to the CDMS catalog, b-type of AAN predicted lines have had large error in millimeter and sub-millimeter wave region. Because b-type transitions have not been measured well, and HK ,h1～h3, and higher constants have not determined well. So in this study, we measured pure rotational spectra from millimeter to sub-millimeter region to improve AAN molecule constant to measure mostly b-type and higher Ka’ transition. B. Bak, E. L. Hansen, F. M. Nicolaisen, O. F. Nielsen, Can. J. Phys., 53, 2183 (1975). G. M. Chaban, J. Phys. Chem. A 2004, 108, 4551-4556 It is quite likely to observe pure rotational spectra in these vibrational excited states. They would be useful for astronomical identification.

in the Vibrational Excited States Rotational spectra in the Vibrational Excited States Last year we reported several vibrational excited states. Extended measurements and assignments.

Experiment by Using Frequency-modulated sub-millimeter wave spectrometer Measured region:114～450 GHz Sample pressure:about 8×10-3 Pa. Glass Cell Oscilloscope Filter PSD Modulator PC Frequency Synthesizer Rb clock GPS ×n Pirani gauge Diffusion pump Detector Amp Gas Multiplier In our experiment, we used Frequency-modulated sub-millimeter wave spectrometer in Toho Univ.. Measured region is 122～188 GHz, 372～537 GHz, and 621～661GHz.

Low-lying Vibrational Excited States Symmetry (approximate) Observed Frequency (cm-1)a Force Field Analysis (cm-1) a Ab Initio Frequency (cm-1) b Ab Initio Frequency (cm-1) c Mode Description In-plane 558 595 563 543.4 NCCN bending Out-of plane 370 361 379 377.2 CC≡N bending 247 222 265 259.6 NH2 torsion 216 261 208 204.9 According to the CDMS catalog, b-type of AAN predicted lines have had large error in millimeter and sub-millimeter wave region. Because b-type transitions have not been measured well, and HK ,h1～h3, and higher constants have not determined well. So in this study, we measured pure rotational spectra from millimeter to sub-millimeter region to improve AAN molecule constant to measure mostly b-type and higher Ka’ transition. B. Bak, E. L. Hansen, F. M. Nicolaisen, O. F. Nielsen, Can. J. Phys., 53, 2183 (1975). G. M. Chaban, J. Phys. Chem. A 2004, 108, 4551-4556 M. P. Bernstein, C. W. Bauschlicher Jr., S. A. Sandford, Advances in Space Research 33 (2004) 40–43

Vibrational Excited States Observed Frequency (cm-1) V0: ground state V1: 235 cm-1 V2: second excited state of V1 V3: 247 cm-1 V4: V5: 270 cm-1 V6: 270 cm-1 Observed Frequency (cm-1) Relative intensity Mode Description 558 0.06 NCC bending 370 0.16 NH2-CH2 torsion 247 0.29 NH2 torsion 235 0.31 CCN bending This is example of b-type transitions. We have been able to measure higher Ka lines like that.

Molecular Constants (up to 4th order) (MHz) Ground statea V1 V3 V5 V2 V4 V6 A 30246.48871(102)b 30018.0957(221) 30627.7884(247) 30143.6831(235) 29783.358(173) 30124.62(47) 29744.76(75) B 4761.062547(139) 4776.37008(69) 4769.29691(68) 4764.23719(56) 4791.41572(109) 4783.06114(270) 4779.1111(33) C 4310.748574(139) 4316.76982(72) 4314.62507(53) 4316.43345(36) 4322.60864(85) 4321.17399(240) 4322.68583(237) DJ×103 3.066871(108) 3.07001(132) 3.04225(85) 3.07234(51) 3.07611(41) 3.19565(267) 3.1559(77) DJK×103 -55.29457(138) -50.3290(127) -57.7248(220) -55.0319(109) -45.8207(227) -47.6164(239) -47.824(76) DK×103 714.0755(78) 544.55(280) 854.44(315) 693.71(307) 305.2(86) 523.(117) 23.(305) d1×103 -0.673533(41) -0.675875(209) -0.674772(270) -0.671983(252) -0.67492(45) -0.68442(176) -0.6786(32) d2×103 -0.0299382(96) -0.019652(63) -0.039723(123) -0.026697(95) -0.00867(40) 0.07764(160) 0.0371(34) Relative Intensity 1.00 0.34 0.31 0.17 0.13 0.11 0.06 Vib. Modec n18 n17 n16 2n18 n17 +n18 n16 +n18 ΔE (cm-1) 235 247 370 ～470 ～480? ～605? # of a-type 232 314 258 226 313 106 64 # of b-type 264 85 47 5 J’ 1-74 13-57 12-46 10-50 10-51 13-22 9-19 Ka’ 0-23 0-12 0-11 0-10 0-9 0-5

Summary and Future Plan Thank you for your ATTENTION !! Rotational spectra in 6 vibrational excited levels were assigned and analyzed based on intensity and rotational constants. A few MHz to 10 MHz deviations from the model at high J, K were noted in the analysis. Analysis including the interaction betweeen the vibrational states are planned. This study was supported by KAKENHI. Funding Thank you for your ATTENTION !!