Mitsunori ARAKI, Hiromichi WAKO, Kei NIWAYAMA and Koichi TSUKIYAMA○ Electronic Transition Spectra of Thiophenoxy and Phenoxy Radicals in Hollow cathode discharges Tokyo Univ. Science Mitsunori ARAKI, Hiromichi WAKO, Kei NIWAYAMA and Koichi TSUKIYAMA○ 2018/11/11 2014/06/16

Diffuse Interstellar Bands Electronic Transition A or B Absorption ★ X Diffuse Cloud Optical absorption lines by molecule in diffuse cloud Near infrared ~ optical (line width: 0.5-50Å) First report: 1922 ~600 lines 2018/11/11

What are origins of DIBs ? Optical Transition 　 Ion and/or radical Large Molecule Not Identified yet Identification of DIBs by Laboratory Spectroscopy 2018/11/11

Unidentified molecule How to identify DIBs ? Optical Electronic Transition Space Earth absorption Star Unidentified molecule DIB Lab Molecule Spectrometer Discharge etc Spectra Identification fit 2018/11/11

Cavity Ring Down Spectrometer Pulsed dye laser, 10 Hz, Dn = 0.1 cm-1 Hollow Cathode Discharge Discharge cell - G Electrodes 2018/11/11

Thiophenoxy Radical C6H5S Rotational Profile Model molecule to discuss Non-Boltzmann Distribution in diffuse cloud Radical: Optical Transition 10% of interstellar molecules -> Sulfide Simple PAH Good candidate of DIB Dose it fit to DIBs? 2018/11/11

Reported Laboratory Spectrum Electronic Transition 2A2 ‹- X2B1 DIBs Disturbed LIF Origin × Shibuya et al., Chemical Physics, 121, 237-244, 1988 2018/11/11

HD204827 having DIBs HD204827 The ８th Magnitude Star Galactic Plane Celestial North Pole Galactic Plane HD204827 The ８th Magnitude Star 2018/11/11

DIBs and Reported Laboratory Spectrum HD204827 DIBs Wavelength (Å) 2018/11/11 Hobbs et al., ApJ, 680, 1256 (2008)

DIBs and Present Laboratory Spectrum by CRD HD204827 300K C6H5SH 1000V × High Temperature ○ Rotational Profile Wavelength (Å) 2018/11/11 Hobbs et al., ApJ, 680, 1256 (2008)

Analysis of C6H5S Rotational Profile Simulation of Non-Boltzmann Distribution in Diffuse Cloud Rotational Constants Simulation of Rotational Profile in Diffuse Cloud Comparison with DIBs 2018/11/11

Rotational Constants from Rotational Profile (cm-1) B3LYP/cc-pVTZ 300K Wavelength (Å) 2018/11/11 Pgopher

Non-Boltzmann Distribution in Diffuse Cloud Dark Clouds Collision >> Radiation Diffuse Clouds Less Collision + Radiation Tk = 100K Linear Molecule Oka et al., 2013, ApJ, 773, 42O Tr = 2.73 K Tr = 14.6 K Tr = 80 K 2018/11/11

Non-Boltzmann Distribution in Diffuse Cloud Dark Clouds Collision >> Radiation Diffuse Clouds Less Collision + Radiation Tk = 100K Linear Molecule Oka et al., 2013, ApJ, 773, 42O Tr = 2.73 K Tr = 14.6 K Tr = 80 K C2v Asymmetric Top 2018/11/11 Singlet

Rotation of C2v Asymmetric Top J (Kc) Ka Permanent dipole moment 2018/11/11

Boltzmann Distribution Collision >> Radiation Dark Clouds J = 3 J = 2 High temperature Low temperature J = 1 J = 0 2018/11/11 Ka = 0 Ka = 1 Ka = 2 Ka = 3

Rotation of C2v Asymmetric Top Diffuse Clouds Radiative Cooling a-type J (Kc) Ka No Radiative Cooling Permanent dipole moment 2018/11/11

Distribution in Diffuse Cloud Collision + Radiation (a-type) Diffuse Clouds J = 3 DKa = 0 J = 2 High temperature Low temperature J = 1 J = 0 2018/11/11 Ka = 0 Ka = 1 Ka = 2 Ka = 3

Rotation of C2v Asymmetric Top Diffuse Clouds Slow Down J (Kc) Ka Hot Axis Continuous Rotation Permanent dipole moment 2018/11/11

Analysis of C6H5S Rotational Profile Simulation of Non-Boltzmann Distribution in Diffuse Cloud Rotational Constants Simulation of Rotational Profile in Diffuse Cloud Comparison with DIBs Pgopher 2018/11/11

Rotational Profile in diffuse cloud 2.73 K Non-Boltzmann distribution is important in diffuse clouds. HD204827 Collision 40 K Collision 40 K Radiation 2.73 K 2018/11/11 Wavelength /Å

Distribution in Diffuse Cloud Collision + Radiation (a-type) Diffuse Clouds J = 3 DKa = 0 J = 2 DKa = 2 J = 1 J = 0 2018/11/11 Ka = 0 Ka = 1 Ka = 2 Ka = 3

Distribution in Diffuse Cloud Collision + Radiation (a-type) Diffuse Clouds A(DKa = 0) > A(DKa = 2) ~ Collision The profile can depend on this competition. 2018/11/11

Rotational Profile in diffuse cloud 2.73 K HD204827 Collision 40 K Radiation 2.73 K Narrower limit Wider limit 2018/11/11 Wavelength /Å

Comparison with DIBs No fit No detection HD204827 Wavelength /Å 2018/11/11

Upper Limit of Column Density Simulation of Rotational Profile Band Width of C6H5S: 2Å Theoretical Calculation (TD–B3LYP / cc–pVTZ) Oscillator Strength: f = 0.003 HD204827, Hobbs et al., ApJ, 680, 1256 (2008) Detection threshold: S/N = 5 Upper limit of column density　2×1013 cm-2 2018/11/11

Summary By Cavity Ring Down Spectroscopy Electronic Spectrum of Thiophenoxy Radical C6H5S By Cavity Ring Down Spectroscopy Simulation of Rotational Profile in Diffuse Cloud Upper limit of column density 2×1013 cm-2 Non-Boltzmann distribution is important in diffuse cloud. 2018/11/11

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Einstein Coefficients and Oka Coefficient （1973） J n(J) B↑r B↓r A C↓ C↑ J-1 n(J-1) 2018/11/11

Rotational Distribution Linear Asym top Radiation temp. (dust) Tr = 40 K Kinetic (collisional) temp. (H2) Tk = 2.73 K Oka’s Collisional Coefficient C = 10E-7 Rotational Constant B = 1454 MHz Permanent Dipole Moment m = 3.1 D 2018/11/11

What parameters are determining the rotational profile? With a hot axis or not. With a permanent dipole moment or not. Radiation temperature Tr Kinetic temperature Tk C constant Permanent dipole moment Rotational constants Rotational constants difference Lifetime 2018/11/11