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(Toho Univ. a, Univ. Toyama b ) Chiho Fujita a, Hiroyuki Ozeki a, and Kaori Kobayashi b 2015 Jun 22ndInternational Symposium on Molecular Spectroscopy,

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Presentation on theme: "(Toho Univ. a, Univ. Toyama b ) Chiho Fujita a, Hiroyuki Ozeki a, and Kaori Kobayashi b 2015 Jun 22ndInternational Symposium on Molecular Spectroscopy,"— Presentation transcript:

1 (Toho Univ. a, Univ. Toyama b ) Chiho Fujita a, Hiroyuki Ozeki a, and Kaori Kobayashi b 2015 Jun 22ndInternational Symposium on Molecular Spectroscopy, Illinois

2 Glycine (NH 2 CH 2 COOH) Alanine, Glutamine, etc… Amino acid Protein LifeFreq.(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.

3  Strecker Syntheses (Strecker (1850))  One of the famous reactions that produce amino acid in laboratory. NH 3 + H 2 CO → CH 2 NH + H 2 O CH 2 NH + HCN → NH 2 CH 2 CN NH 2 CH 2 CN + H 2 O → NH 2 CH 2 CONH 2 NH 2 CH 2 CONH 2 + H 2 O → NH 2 CH 2 COOH + NH 3 ammonia formaldehyde methylenimine hydrogen cyanide aminoacetonitrile (AAN) Glycine ( Ugliengo et al. 2011 ) aminoacetamide

4 AANNC 1.4760 Å 1.4760 Å CC’ 1.4611 Å 1.4611 Å C’N’ 1.1594 Å 1.1594 Å CH 1.0940 Å 1.0940 Å NH 1.0138 Å 1.0138 Å NCC’114.54° HCH102.4° HNC109.6° HNH107.3° CC’N’180.0° Pickett (1973) Hydrogen Carbon Nitrogen N N’ C C’

5 MacDonald & Tyler 1972  Measured AAN spectra in the microwave region. a-type: 3 lines b-type: 2 lines a-type: 3 lines b-type: 2 linesPickett1973  Measured AAN and its deuterated isotopologues (NHD-, ND 2 -) spectra in microwave region. (NHD-, ND 2 -) spectra in microwave region.  Determined electric dipole moment. μ a =2.577(7)D, μ b =0.5754(10)D μ a =2.577(7)D, μ b =0.5754(10)D Brown et al. 1977  Determined hyper fine coupling constant of nitrogen nuclei. 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. 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.

6 CDMS  Belloche et al. (2008) succeeded to detect AAN’s millimeter wave spectra towards Sgr B2(N)!! AAN’s millimeter wave spectra towards Sgr B2(N)!!  Detected region 80~260GHz  Detected line 51 a-type transitions GHz

7 Parameter (MHz)Motoki et al. Belloche et al.Bogey et al. A30246.48871(102)30246.4561(71)30246.755(18) B 4761.062547(139) 4761.06102(84) 4761.06169(44) C 4310.748574(139) 4310.75123(76) 4310.75076(41) D J ×10 3 3.0666871(108) 3.06853(68) 3.06545(48) D JK ×10 2 -5.529457(138) -5.52986(69) -5.5293(10) DKDK 0.7140755(78) 0.67662(99) 1.0483(20) d 1 ×10 3 -0.673533(41) -0.67160(40) -0.67160(16) d 2 ×10 3 -0.0299382(96) -0.028893(106) -0.03096(13) H J ×10 9 9.535(30) 9.593(276) 9.47(18) H JK ×10 6 -0.12406(51) -0.1201(72) -3.067(14) H KJ ×10 6 -2.7126(81) -2.6861(268) 6.85(13) H K ×10 3 0.0523(21) 0.030 0.034479(90) h 1 ×10 9 3.8722(146) 2.989(225) - h 2 ×10 9 0.4749(62) - -0.962(93) h 3 ×10 9 0.0523(21) - 2.623(59) L J ×10 12 -0.0360(28) - - L JK ×10 9 -0.00539(133) - -3.58(22) L KJ ×10 12 0.1858(157) - 8.45(98) L K ×10 6 -0.0044049(176) - 17.08(94) S K ×10 9 - - 52.5(33)

8  It is quite likely to observe pure rotational spectra in these vibrational excited states.  They would be useful for astronomical identification. a.B. Bak, E. L. Hansen, F. M. Nicolaisen, O. F. Nielsen, Can. J. Phys., 53, 2183 (1975). b.G. M. Chaban, J. Phys. Chem. A 2004, 108, 4551-4556 Observed Frequency (cm -1 ) a Ab Initio Frequency (cm -1 ) b Mode Description 558563  NCC bending 370379  NH 2 -CH 2 torsion 247265  NH 2 torsion 235208  CC  N bending

9  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

10  The rotational constants are expected to be similar to those in the ground state.  Similar pattern with about 1/3 intensity were expected.  When J of a-type R-branch becomes high, transitions of Ka=0 and 1 become closer and look like a doublet.  The second excited state was found based on the extension of the ground state and the first excited state.

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12 a.B. Bak, E. L. Hansen, F. M. Nicolaisen, O. F. Nielsen, Can. J. Phys., 53, 2183 (1975). b.G. M. Chaban, J. Phys. Chem. A 2004, 108, 4551-4556 c.M. P. Bernstein, C. W. Bauschlicher Jr., S. A. Sandford, Advances in Space Research 33 (2004) 40–43 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-plane558595563543.4  NCCN bending Out-of plane 370361379377.2  CC ≡ N bending Out-of plane 247222265259.6  NH 2 torsion In-plane216261208204.9  NCCN bending

13 V0: ground state V1: 235 cm-1 V2: second excited state of V1 V3: 247 cm-1 V4: V5: 270 cm-1 Observed Frequency (cm -1 ) Relative intensity Mode Description 5580.06  NCC bending 3700.16  NH 2 -CH 2 torsion 2470.29  NH 2 torsion 2350.31  CC  N bending

14  Intensity suggests that the three vibrational levels correspond to the three lowest vibrational excited states.  The closeness of the two vibrational excited states indicate possibility of strong perturbation.  A few MHz to 10 MHz deviations from the model at high J, K were noted in the analysis.

15  Pure rotational spectra of AAN in the vibrational excited states were measured.  Analysis including the interaction between the vibrational states are planned.  This study was supported by KAKENHI.


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