Spectrochemistry

 

    @Department of Chemistry, Faculty of Science, Okayama University

                                                          Tsushima-naka 3-1-1, Okayama 700-8530, Japan

                                      

Kentarou Kawaguchi   (Prof.)          Tel & Fax: 81-86-251-7848

                                          e-mail :okakent(@cc.okayama-u.ac.jp)

Jian Tang                        (Associate Prof.)    Tel : 81-86-251-7849

                                          e-mail :jtang(@cc.okayama-u.ac.jp)

Yuki Miyamoto              (Assistant Prof.)    

                                          e-mail :miyamo-y(@cc.okayama-u.ac.jp)

 

Chen Wang                     (D1)

Hisayuki Nagahiro         (M2)

Tomomi Fujiyama         (M2)

Kazuhiro Nishiguchi      (M1)

Rie Akiyama                  (B4)

Mina Imai                       (B4)

Chihoko Kitayama        (B4)

 

 

OB & OG (2010-)

Yusuke Okabayashi      (D3 -2013.3)                         

Hiroki Ooe                      (M2 -2013.3)

Taturo Narahara           (M2 -2013.3)

Ryuji Fujimori                (D3 -2012.3)

Hiroki Ohiwa                  (M2 -2012.3)

Natuko Shimizu             (M2 -2012.3)

Ken-ichiro Takihara     (M2 -2012.3)

Chisato Masaki             (B4 -2012.3)

Naomi Ikeda                   (M2 -2011.3)

Shota Fukutomi             (B4 -2011.3)

Takaki Murakami          (B4 -2011.3)

Pradeep R. Varadwaj   (JSPS -2010.9)

 

 

Co-workers

Oleg Baskakov (Kharkiv National University, Ukraine)

Svatopluk Civis (J. Heyrovsky Institute, Czech Republic)

Mukul Narayan Deo (BARC, India)

 

Research@

 

 

I.  Astrochemistry

 

(1) Circumstellar envelope of IRC+10216

 

Observation of C8H- towards IRC+10216

 Five rotational lines of the C8H- ion were observed in the circumstellar envelope of IRC+10216 with the Nobeyama 45-m telescope. An improved value of the column density [(2.6 } 0.4) ~1012 cm-2 for C8H- yielded a [C8H-]/[C8H] ratio of 0.37 nearly 4 times larger than the [C6H-]/[C6H] ratio (0.086) and nearly 1500 times the [C4H-]/[C4H] ratio (0.00024), which may indicate more efficient formation of longer carbon chain anions. The excitation temperature of C8H- (16 } 2 K) derived here is somewhat lower than that of the two smaller anions C6H- (32 K) and C4H- (23 K) in IRC+10216.

 

Analysis of radio astronomical data of the negative ion C6H- in IRC+10216

 

Radio astronomical data of C6H- observed with the Nobeyama 45-m and IRAM 30-m telescopes have been analyzed by the local thermodynamic equilibrium approximation to give the column density of 6.1-8.0 x 1012 cm-2 and the excitation temperature of 32}3 K, with an assumed source size of 30}3. The abundance of C6H- was estimated to be 8.6 % of C6H. The observed line shapes of C6H- and C6H indicate that the distribution of C6H- is in inner region than C6H. The production mechanism of C6H- is discussed.

 

 

(2) Diffuse clouds

 

Search for C2-

 

     A search has been carried out for the C2- ion in diffuse clouds toward HD 23180,

HD 24912, HD 24398, HD 46711, and HD 50064 using the HIDES spectrometer on the Okayama 188-cm telescope. An upper limit of 8.3 x 1010  - 1.8 x 1012 cm-2 has been obtained for the C2- column density. The upper limit value 3.8 x 1011 cm-2  toward HD 23180 is two order of magnitude smaller than that of the C2 radical. Possible production mechanisms for C2- are discussed. 

 

Observation of diffuse interstellar bands (DIBs)

We observed a series of five or six DIBs lines with a nearly constant spacing of about 35 cm-1 around 6800 Å by using a spectrometer with a wavelength resolution of l/Dl=75000. We obtained similar intensities in HD 21389, HD 41117, HD 43384, HD 198478, and HD 206165. As a candidate of these DIBs carrier, a perpendicular vibronic band of CH2X type molecules has been proposed by Glinski and Nuth (PASP, 107, 453, 1995), where X is a heavy atom or linear carbon chain. Although the 35 cm-1 intervals are interpreted by assuming only ortho lines are detected, we could find none of spectral lines originating from para levels. We simulated the spectra of quasi-linear molecules such as HNCX, and found that a high temperature is required for explanation of the observed spectra. Thus we concluded that the carrier of series of DIBs appeared near 6800 Å is not explained by the perpendicular vibronic band of CH2X or quasi linear HNCX type molecules. Other candidates are discussed. 

 

(3) Chemistry in External Galaxies

 

Several transitions of the cyclopropenylidene (cyclic-C3H2) molecule have been observed in the 83 - 218 GHz region toward NGC 253 and M@82@with the Nobeyama 45-m and IRAM 30-m telescopes. Assuming local thermodynamic equilibrium, the rotational temperatures were determined to be 10.8 } 2.4 and 11.5 } 3.0 K for NGC 253 and M 82, respectively, where the errors indicate three standard deviations (3 s). The column densities of cyclic- yclic-C3H2 were determined to be N@(NGC@253) = (2.7 }@1.1) x 1013 and N@(M@82) = (1.9 } 0.9) x@1013 cm-2. Large velocity gradient calculations were applied to estimate kinetic temperatures of around 60 K@for NGC 253 and M~82.@ Considering the present result and recent observations of NH3 in both galaxies, molecular production mechanisms are discussed.

 

II. Laboratory spectroscopy

 

(1) Time-resolved Fourier transform spectroscopy with Bruker IFS 120HR

 

By using a high-resolution Bruker IFS 120 HR, a TR-FTS method has been developed with the help of a microcontroller SX, where a maximum of 64 time-resolved data are recorded with a preset time interval in a single scan of the interferometer. The time resolution is 1 msec, limited by the response time of the detector system used. This method has been applied to a pulsed discharge in an Ar and H2 mixture to observe time profiles of ArH+ and ArH emission spectra. Figure 1 shows an example of time-resolved spectra observed from a discharge in an Ar and H2 mixture. Figure 2 showsobserved time profiles of infrared emission of ArH and ArH+. Electronic transitions of He2 have been observed in the infrared region with this method, and from the time profiles, He2 in Rydberg states with higher energy than the b3P state is found to be produced efficiently in afterglow plasma. Fifteen bands in the 2300-8000 cm-1 region have been assigned by using previously reported data from the optical region. A new band from the 5f state has been assigned for the first time through the 5f-4d band in the 2600 cm-1 region.


Figure1.A part of the observed emission spectrum from a discharge in an Ar 465 Pa and H2 2.0 Pa mixture. The discharge was applied in the interval 0 – 20msec with a peak current of 0.5 A. The strong peaks are due to Ar atomic

lines. Many weak lines seen around the second peak of Ar appear to be due to ArH.

 

 

image001

 

 

Figure 2DObserved time profiles of emission intensities for ArH+ v=1-0, R(7) [2725.5843 cm-1] and ArH 5p-6s, R(6.5) [3700.774 cm-1] lines. A discharge pulse was applied during 0 - 20 msec with a peak current of 800 mA. The partial pressures are Ar 3.6 Torr and H2 0.4 Torr (high H2 pressure condition). The abscissa values are relative intensities of two lines. 

 

 
image004

 

 

 

 

 

(1-a)  Time-resolved Fourier transform emission spectroscopy of A2ƒฎ–X2ƒฐ+ infrared transition of the CN radical

 

S. Civiš1, T. Šedivcová-Uhliková2, P. Kubelík1 , K. Kawaguchi3

The A2P-X2S+ Dv = -3 bands of the 12C14N radical have been observed by time-resolved Fourier transform spectroscopy in the 1850-3100 cm-1 region with a wavenumber resolution of 0.025 cm-1. The radical was produced in a pulsed positive column discharge in a cyanogene and helium mixture. Seven bands of v = 0-3, 1-4, 2-5, 3-6, 4-7, 5-8, and 6-9 were analyzed to give the molecular constants of each state by least-squares fitting of 801 lines. The pulsed discharge was found to be efficient for production of CN in the excited A2P state. The vibrational excitation temperature was determined to be 6680}835 K and 6757}500 K for A2P and X2S+ states, respectively. The population of A2P was found to be 1/173 of that of the X2S+ state in the time after turning off the discharge. 

 

(1-b) Time-resolved Fourier transform infrared emission spectroscopy of laser ablation products

K. Kawaguchi, N. Sanechika, Y. Nishimura, R. Fujimori, T. N. Oka, Y. Hirahara, A. I. Jaman, and S. Civiš

 

Time-resolved Fourier transform infrared spectroscopy was applied for observations of emission spectra from ablation products induced by a Nd:YLF laser with a 2.5 kHz repletion rate. The infrared emission spectra from Fe, Cu, Zn, and Al atoms were observed in the 2.5-5 mm region. The observed emission spectrum from iron ablation in the 2500 cm-1 region agrees very well with solar absorption spectrum, where new lines have been detected in the present experiment in addition to the lines observed from a hollow cathode discharge. When O2 was added to the carbon ablation, emissions from vibrationally excited CO were observed with non-equilibrium vibrational distribution.

 

  

(2) Laboratory mill-meter wave spectroscopy

                      

 [MgO]

     Pure rotational transitions of MgO in the a3Pi state and the ground X1S+ state (v=1-3) were observed in the 210-400 GHz region. The MgO molecule was produced by a DC discharge in a mixture of Mg vapor and N2O. A simultaneous deperturbation analysis for the X1S+, a3P, and A1P states was carried out for the observed transition frequencies including previous high-resolution data, where the energy levels were calculated by diagonalizing the energy matrix including the spin-orbit and orbit-rotation interactions among three electronic states with vibrational levels up to v=9. A centrifugal term of the spin-orbit interaction between the a3Pi and X1S+ states was newly introduced to improve quality of the fitting, to explain the observed L-type doubling of the a3Pi state.   

 

[Alanine]

Millimeter-wave spectroscopy of a-alanine was carried out by using continuous  molecular beam.@The sample of a-alanine was heated up to 200-210 K, and flowed with Ar buffer gas through a nozzle with a 0.4 mm diameter. Fifty-five lines of conformer I and 35 lines of conformer IIa of a-alanine were newly measured in 80~99 and 160~180 GHz regions. A least squares analysis of the presently observed transitions combined with the previously observed millimeter wave data below 71 GHz and Fourier transform microwave data gave a set of improved molecular constants which are useful for prediction of the transition frequencies in high frequency region. The rotational temperature of conformer I in the continuous molecular beam was estimated to be 29.9 } 6.5 K.  

 

[BiS]

This paper reports the 6 400-7 400 cm-1 Fourier-transform (FT) near-infrared (NIR) emission spectrum of the BiS X22P3/2® X12P1/2 fine structure bands as well as the millimeterwave rotational spectrum of the X12P1/2 state.  For the FTNIR observations, BiS was produced by reaction of bismuth with sulfur vapor and excited by energy transfer from metastable oxygen, O2(a1Dg), in a fast-flow system. As was the case for  BiO [O. Shestakov et al., J. Mol. Spectrosc. 190 (1998) 28-77],  the 0.5 cm-1 resolution spectrum revealed a number of strong bands in the Dv=0 and }1 sequences which showed perturbed band spacings, band shapes, and intensities due to avoided crossing of the X22P3/2 and A14P3/2 potential curves for vŒ ³ 4 of X22P3/2. The millimeterwave rotational spectrum of BiS in its X12P1/2 state was observed when BiS was produced in a high-temperature oven by a discharge in a mixture of Bi vapor and CS2.  The signal to noise ratio was markedly improved by using a White-type multipath cell. Ninety seven features from J¢ = 23.5 to J¢ = 41.5 were measured between 150-300 GHz.  Analysis of the 0.5 cm-1 resolution FT spectrum yielded the fine structure splitting and vibrational constants of the states. A simultaneous analysis of millimeterwave and a 0.005 cm-1 FT spectrum of the 0-0 band of the NIR system was carried out to give precise rotational, fine, and hyperfine constants for the X12P1/2 and X22P3/2 states.   The results are consistent with those reported earlier for BiO and indicate only a slight decrease in the unpaired electron density in the 6p(p*) orbital on the Bi atom.

 

 

Recent Publications

 

2008

 

 Time-resolved Fourier transform emission spectroscopy of A2ƒฎ–X2ƒฐ+ infrared transition of the CN radical, S. Civiš, T. Šedivcová-Uhliková, P. Kubelík, K. Kawaguchi, J. Mol. Spectrosc. 250, 20-26 (2008)

 

 Millimeter-wave spectroscopy of a-alanine, Y. Hirata, S. Kubota, S. Watanabe, T. Momose, and K. Kawaguchi, J. Mol. Spectrosc. 251, 314-318 (2008)

 

 Time-resolved Fourier transform infrared emission spectroscopy of laser ablation products, K. Kawaguchi, N. Sanechika, Y. Nishimura, R. Fujimori, T. N. Oka, Y. Hirahara, A. I. Jaman, and S. Civiš, Chem. Phys. Letters 463, 38-41 (2008)

 

 Near-infrared Fourier-transform and millimeterwave spectra of the BiS radical

     K. Izumi, E. A. Cohen, K. D. Setzer, E. H. Fink, and K. Kawaguchi, J. Mol. Spectrosc. 252, 198204(2008)

 

2007

 

Fourier transform emission spectroscopy of the Dv=1 bands of the 18OH radical, I. Morino, K. Takagi, and K. Kawaguchi, Mol. Phys. 105, 841-848 (2007)

 

Observation of C8H- towards IRC+10216,  K. Kawaguchi, R. Fujimori, S. Aimi,

    S. Takano, E. Y. Okabayashi, H. Gupta, S. Brünken, C. A. Gottlieb, M. C. McCarthy, and P. Thaddeus, Publ. Astron. Soc. Japan, 59, L47-50 (2007)

 

Astronomical detection of C4H, the second interstellar anion, J. Cernicharo1, M. Guélin, M. Agúndez1, K. Kawaguchi, M. McCarthy, and P. Thaddeus,  Astron. Astrophy. 467, L37-40 (2007).

 

Analysis of radio astronomical data of the negative ion C6H- in IRC+10216, Y. Kasai, E. Kagi, and K. Kawaguchi, Astrophys. J. 661, L61-64 (2007)

 

2006

 

Time-resolved Fourier Transform infrared emission spectroscopy of H3+ molecular ion, S. Civis, P. Kubat, S. Nishida, and K. Kawaguchi, Chem. Phys. Lett. 418, 448-453 (2006).

 

Microwave spectroscopy of MgO in the a3P and X1S states, E. Kagi, and K. Kawaguchi, J. Mol. Struct. 795, 179-184 (2006).

 

The rotational spectrum of BiO radical in its X1 2P1/2 and X2 2P3/2 states, E. A. Cohen, D. M. Goodridge, K. Kawaguchi, E. H. Fink, and K. D. Setzer, J. Mol. Spectrosc. 239, 16-23 (2006).

 

Correlation between Nuclear Spin Ratio of Cyclic C3H2 and Chemical Evolution in TMC-1 Cores, Y. Morisawa, M. Fushitani, Y. Kato, H. Hoshina, Z. Simizu, S. Watanabe, Y. Miyamoto, Y. Kasai, K. Kawaguchi, and T. MomoseAstrophys. J. 642, 954-965 (2006).

 

Observational studies relating to diffuse interstellar bands, H. Tada, K. Kawaguchi, H. Izumiura, S. Civis, and T. Sedivcova, eAstrochemistry From laboratory studies to astronomical observationsf, AIP Conference Proceedings 855, Eds. R. Kaiser, P. Bernath, Y. Osamura, S. Petrie, A. M. Mebel, pp219-224 (2006) 

 

‚Q‚O‚O‚T

High resolution emission FTIR spectra of the 4p – 5s and 5p - 6s bands of ArH

O. I. Baskakov, S. Civis, and K. Kawaguchi, J. Chem. Phys., 122, 114314(11) (2005)

 

Search for CCH, NCO, and NCS negative ions in molecular clouds

Y. Morisawa, H. Hoshina, Y. Kato, Z. Simizu, S. Kuma, N. Sogoshi, M. Fushitani, S.  Watanabe, Y. Miyamoto, T. Momose, Y. Kasai, and K. Kawaguchi, Publ. Astron. Soc. Japan, 57, 325-334 (2005)

 

 Time-resolved Fourier transform infrared spectroscopy : application to pulsed discharges

K. Kawaguchi, Y. Hama, and S. Nishida, J. Mol. Spectrosc.232, 1-13 (2005)

 

 High angular resolution observations of the (J, K)=(1, 1), (2,2), and (3,3) transitions of ammonia in NGC 253, S. Takano, P. Hofner, G. Winnewisser, N. Nakai, and K. Kawaguchi, Publ. Astron. Soc. Japan, 57, 549-561 (2005)

 

Search for C2 in Diffuse Clouds, S. Civis, Y. Hosaki, E. Kagi, H. Izumiura, K. Yanagisawa, T. Sedivcova, and K. Kawaguchi, Publ. Astron. Soc. Japan, 57, 605-609 (2005)

 

High-resolution FTIR measurement of the 2ƒห8 band of methylene fluoride (CH2F2
P. J. Singh, M.N. Deo and K. Kawaguchi, J. Mol. Spectrosc. 234, 157-169 (2005).

 

‚Q‚O‚O‚S

Time-resolved Fourier transform infrared emission spectroscopy of He2 produced by a pulsed discharge

Yukio Hosaki, Svatopluk Civiš, and Kentarou Kawaguchi

Chem. Phys. Letters, 383, 256-260 (2004).

 

A 8.8-50 GHz complete spectral line survey toward TMC-1 I. survey data, N. Kaifu, M. Ohishi, K. Kawaguchi, S. Saito, S. Yamamoto, T. Miyaji, K. Miyazawa, S. Ishikawa, C. Noumaru, S. Harasawa, M. Okuda, and H. Suzuki, Publ. Astron. Soc. Japan, 56, 69-173 (2004) 

 

Observations of cyclopropenylidene (cyclic-C3H2) in the external galaxies NGC 253 and M 82, T. Oike, K. Kawaguchi, S. Takano, and N. Nakai, Publ. Astron. Soc. Japan, 56, 431-438 (2004)

 

High-resolution FTIR measurement of the small nu, Greek4 band of methylene fluoride-d2 

A. Shastri, M. N. Deo and K. Kawaguchi, J. Mol. Spectrosc. 227, 195-201(2004)

 

The infrared spectrum of CN in its ground electronic state

    V. Horká, S. Civiš, V. Špirko, and K. Kawaguchi, Coll. Czech. Chem. Commun. 69, 73-89 (2004)

 

Infrared emission studies of the A3ƒฐX3ƒฎ electronic transition of the SiC radical 

M. N. Deo, and K. Kawaguchi, J. Mol. Spectrosc. 228, 76-82 (2004)

 

New rotation-vibration band and potential energy function of NeH+ in the ground electronic state

S. Civis, J. Sebera, V. Spirko, J. Fiser, WP Kraemer, K. Kawaguchi, J. Mol. Struct. 695, 5-11 (2004)

‚Q‚O‚O‚R

Time-resolved Fourier transform infrared spectroscopy of pulsed discharge products

   K. Kawaguchi, O. Baskakov, Y. Hosaki, Y. Hama, and C. Kugimiya

   Chem. Phys. Letters, 369, 293-298 (2003).

 

Has MgCCCN been detected within the envelope of IRC+10216?, S. Petrie, E. Kagi, and K. Kawaguchi, Mon. Not. R. Astron. Soc. 343, 209-214 (2003).

 

‚Q‚O‚O‚Q

Multi-transitional observations of methanol in Comet Hale-Bopp (1995 O1)

M. Ikeda, K. Kawaguchi, S. Takakuwa, A. Sakamoto, K. Sunada, and T. Fuse, Astron. Astrophys. 390, 363-367 (2002).

 

Millimeter- and submillimeter-wave spectra of 13CD2F2

    R. DfCunha, M. N. Deo, and K. Kawaguchi, J. Mol. Spectrosc. 213, 46-50 (2002).

 

Observations of ammonia in external galaxies I. NGC 253 and M82

    S. Takano, N. Nakai, and K. Kawaguchi, Publ. Astron. Soc. Japan, 54, 195-207 (2002).

 

Observations of H3+ in the diffuse interstellar medium

1.   J. McCall, K. H. Hinkle, T. R. Geballe, G. H. Moriaty-Schieven, N. J. Evans II, K. Kawaguchi, S. Takano, V. V. Smith, and T. Oka,@Astrophys. J. 567, 391-406 (2002).

 

Astronomical vibrational spectroscopy

K. Kawaguchi

in Handbook of Vibrational Spectroscopy, J. M. Chalmers and P. R. Griffiths (Eds), John Wiley & Sons, Ltd, Volume 4, pp.2803-2822 (2002).

 

‚Q‚O‚O‚P

High-resolution Fourier transform infrared spectra of CH3 n3 and CH2D n4 bands

K. Kawaguchi, Can. J. Phys. 79, 449-459 (2001).

 

The ortho-to-para ratio and the chemical properties of C3H2 in dark cloud cores

S. Takakuwa, K. Kawaguchi, H. Mikami, and M. Saito, Publ. Astron. Soc. Japan, 53, 251-257 (2001).

 

Experimental determination of the vibrational transition moment of NeH+ in the 1S+ ground state

S. Civis, R. DfCunha, and K. Kawaguchi, J. Mol. Spectrosc. 210, 127-131 (2001).

 

‚Q‚O‚O‚O

 

Identification of SH Dv=1 ro-vibrational lines in R Andromedae

I. Yamamura, K. Kawaguchi, and S. T. Ridgway, Astrophys. J. 528, L33-L36 (2000).

 

Rotational spectrum of the MgN13C radical

E. Kagi, and K. Kawaguchi, J. Mol. Spectrosc. 199, 309-310 (2000).

 

High-resolution FTIR study of the n2 band of CH2F2 and Coriolis interaction between the n2 and

n8 states

M. N. Deo, K. Kawaguchi, and R. DfCunha, J. Mol. Struc. 517-518, 187-195 (2000).

 

Observations of ammonia in external galaxies II. Maffei 2

S. Takano, N. Nakai, K. Kawaguchi, and T. Takano, Publ. Astron. Soc. Japan, 52, L67-L71 (2000).