arXiv subjects

Norio Ota

Publications and source records attributed to Norio Ota.

At least 19 recordsLinked to original sources

arXiv2024

Near Infrared Diffuse Interstellar Bands Characterized by Fullerene and Graphene Molecules

Astronomical near-infrared Diffuse-Interstellar-Bands (DIBs) were characterized by pure carbon Fullerene and Graphene molecules comparing with laboratory experiment and with Time-Dependent Density-Functional-Theory (TD-DFT) analysis. It is well known that two large DIBs of Fullerene cation (C60)+ at 9577A and 9632A coincide well with laboratory experiments. Those are thought to be split bands by the Jahn-Teller molecular deformation. In our TD-DFT calculation, those are reproduced by degenerated bands at 9549A and 9552A before deformation. Cation enriching experiment by Strelnikov et al. suggested longer wavelength two bands of DIB10542 and DIB10610 (observed by Hamano et al.), which may split from calculated 10410A and 10411A. Also, we noticed shorter wavelength experimental band around 8550A, which may relate to calculated 8677A and 8686A. We challenged such analysis on Graphene molecules as like (C54) (C53) (C52) and (C51), which are carbon hexagon and pentagon combined molecules. Calculation could reproduce many near-infrared bands. Calculated bands of (C54) suggest that one DIB among (DIB9577, DIB9632, or DIB9673) may correspond to one of (DIB10361, DIB10394, or DIB10439). Calculated bands of (C51) suggest that one of (DIB9686, DIB9987, or DIB10006) may relate to one of (DIB10262 or DIB10288). Combining astronomical observation, laboratory experiment, and quantum chemical analysis, we could suggest carrier candidates of DIBs.

astro-ph.GA↗

arXiv2023

Contribution of Graphene Molecules C$_{53}$ C$_{52}$ C$_{51}$ on Astronomical Diffuse Interstellar Bands (DIB)

This molecular orbital analysis predicts that pure carbon graphene molecules would play an important role on astronomically observed Diffuse Interstellar Bands (DIB), rather than fullerene. Laboratory experiments precisely coincided with observed DIB bands as studied by E. Cambell et al., which were considered to originate from mono-cation fullerene-(C$_{60}$)$^{1+}$. To check theoretically a molecular orbital excitation of (C$_{60}$)$^{1+}$ was calculated by the Time-Dependent DFT. Calculated two bands were close to observed DIBs, but there were two problems, that the oscillator strength was zero, and that other three DIBs could not be reproduced. Laboratory experiments was the mass spectroscopic one filtering m/e=724, to suggest fullerene-(C$_{60}$)$^{1+}$ combined with He. However, there were other capabilities, as like He-atom intercalated 3D-graphite, [graphene(C$_{53}$)$^{1+}$--He--(C$_7$)], [graphene(C$_{51}$)$^{1+}$--He--(C$_9$)] and so on. A family of graphene (C$_{53}$), (C$_{52}$) and (C$_{51}$) was calculated. Results show that an astronomically observed 957.74nm band was reproduced well by calculated 957.74nm, also confirmed by laboratory experiment of 957.75nm. Other observed 963.26, 936.57 and 934.85nm bands were calculated to be 963.08, 935.89 and 933.72nm. Moreover, experimental 922.27nm band was calculated to be 922.02nm, which is not yet astronomically observed. Similarly, experimental 925.96, 912.80, 909.71 and 908.40nm bands were calculated to 926.01, 912.52, 910.32 and 908.55nm. It should be emphasized that graphene molecules may be ubiquitously floating in interstellar space.

astro-ph.GA↗

arXiv2023

Astronomical Infrared Bands and Diffuse Interstellar Bands Both Reproduced by Hydrocarbon Pentagon-Hexagon Combined PAH Molecules

This study theoretically predicts the specific Polycyclic Aromatic Hydrocarbon (PAH) molecules to reproduce both astronomically observed Infrared Bands (IR) and Diffuse Interstellar Bands (DIB). In our recent paper, we could reproduce IR by the hydrocarbon pentagon-hexagon combined PAH molecules using Density Functional Theory (DFT). Found molecules were (C53H18), and (C23H12) with two carbon pentagons among hexagon networks. Origin of DIB may come from the molecular orbital excitation. We applied Time-Dependent DFT calculation. In case of (C53H18), by comparing calculation with observed DIB, we found 7 coincide bands among 42 calculated bands within observed band width. For example, neutral (C53H18) shows calculated 577.35nm band coincide well with observed DIB at 577.95nm within 1.55nm observed band width. Mono-cation shows calculated 627.87nm correspond to observed 627.83nm, also for di-cation calculated 635.89nm to observed 635.95nm. For smaller size molecule (C23H12), we found 5 coincide bands, of which mono-cation shows calculated 713.92nm coincide with observed 713.80nm, di-cation shows calculated 653.27nm correlate to observed 653.21nm. By such quantum-chemical survey, we could predict specific PAH molecules floating in interstellar space.

astro-ph.GA↗

arXiv2023

Classifying Protoplanetary disks Infrared Spectrum and Analysis by c-C$_3$H$_2$ C$_5$H$_5$ C$_9$H$_7$ C$_{12}$H$_8$ C$_{23}$H$_{12}$ and C$_{53}$H$_{18}$ to be Capable Template for Biological Molecule

Protoplanetary disk around a just born young star contains a lot of cosmic dust. especially polycyclic-aromatic-hydrocarbon (PAH), which would become basic component to create biological organics. This study classified many astronomically observed infrared spectra of protoplanetary disks to three typical spectra. Type-A show well known astronomical bands of 6.2, 7.8, 8.6 and 11.3 micrometer. Whereas Type-B included unknown complex bands. Type-(A+B) was their mixed type. We tried to find specific molecule by Density Functional Theory (DFT) calculation. We found that Type-A could be explained by large PAH molecules of (C$_{23}$H$_{12}$) and (C$_{53}$H$_{18}$), which are hexagon-pentagon combined molecular structure. Background molecule of Type-B was smaller ones of (c-C$_3$H$_2$), (C$_5$H$_5$), (C$_9$H$_7$) and (C$_{12}$H$_8$). Type-(A+B) was reproduced well by mixing those molecules of A and B. Astronomical detailed observation shows that central star of Type-A has larger mass and higher temperature than that of Type-B. This suggests that at very early stage of our solar system, our protoplanetary disk had been made up by Type-B molecules. It was interesting that (C$_5$H$_5$) and (C$_9$H$_7$) of Type-B molecules has similar molecular structure with biological nucleic-acid on our earth. Type-B molecules was supposed to become the template for synthesizing biological organics and finally for creating our life.

astro-ph.GA↗

arXiv2021

Magnetism of Fullerene C60 Compared with Graphene Molecule by DFT Calculation, Laboratory Experiment and Astronomical Observation

Magnetism of fullerene C60 was studied by three methods of the density functional theory (DFT) calculation, laboratory experiment and astronomical observation. DFT revealed that the most stable spin state was non-magnetic one of Sz=0/2. This is contrary to our recent study on void induced graphene molecules of C23 and C53 to be magnetic one of Sz=2/2. Two graphene molecules combined model suggested that two up-spin at every carbon pentagon ring may cancel each other to bring Sz=0/2. Similar cancelation may occur on C60. Molecular vibrational infrared spectrum of C60 show four major bands, which coincide with gas-phase laboratory experiment, also with astronomically observed one of carbon rich planetary nebula Tc1 and Lin49. However, there remain many unidentified bands on astronomical one. We supposed multiple voids on graphene sheet, which may create both C60 and complex graphene molecules. It was revealed that spectrum of two voids induced graphene molecule coincident well with major astronomical bands. Simple sum of C60 and graphene molecules could successfully reproduce astronomical bands in detail.

astro-ph.GA↗

arXiv2021

Void defect induced magnetism and structure change of carbon material-3, Polycyclic aromatic hydrocarbon

Void-defect induced magnetism of graphene molecule was recently reported in our previous paper of this series study. This paper investigated the case of hydrogenated graphene molecule, in chemical term, polycyclic aromatic hydrocarbon (PAH). Molecular infrared spectrum obtained by density functional theory was compared with astronomical observation. Void-defect on PAH caused serious structure change. Typical example of C23H12 had two carbon pentagon rings among hexagon networks. Stable spin state was non-magnetic singlet state. This is contrary to pure carbon case of C23, which show magnetic triplet state. It was discussed that Hydrogen played an important role to diminish magnetism by creating an SP3-bond among SP2-networks. Such a structure change affected molecular vibration and finally to photoemission spectrum in infrared region. The dication-C23H12 showed featured bands at 3.2, 6.3, 7.7, 8.6, 11.2, and 12.7 micrometer. It was surprising that those calculated bands coincided well with astronomically observed bands in many planetary nebulae. To confirm our study, large size molecule of C53H18 was studied. Calculation reproduced again similar astronomical bands. Also, small size molecule of C12H8 showed good coincidence with the spectrum observed for young stars. This paper would be the first report to indicate the specific PAH in space.

astro-ph.GA↗

arXiv2021

Void defect induced magnetism and structure change of carbon materials-1, Graphene nano ribbon

Void defect is a possible origin of ferromagnetic like feature of pure carbon material. Applying density functional theory to void defect induced graphene nano ribbon (GNR), a detailed relationship between multiple spin state and structure change was studied. An equitorial triangle of an initial initial void having six electrons is distorted to isosceles triangle by rebonding carbon atoms. Among possible spin states, the most stable state was Sz=2/2. The case of Sz=4/2 is remarkable that initial flat ribbon turned to three dimentional curled one having highly polarized spin configuration at ribbon edges. Total energy of Sz=4/2 was very close to that of Sz=2/2, which suggests coexistence of flat and curled ribbons. As a model of three dimensional graphite, bilayered AB stacked GNR was analyzed. Spin distribution was limited to the void created layer. Distributed void triangle show 60 degree clockwise rotation for differrent site void, which was consistent with experimental observation using the scanning tunneling microscope. (To be published on Journal of the Magnetic Society of Japan, 2021 )

cond-mat.mtrl-sci↗

arXiv2021

Void defect induced magnetism and structure change of carbon material-2, Graphene molecules

Void-defect is a possible origin of ferromagnetic feature on pure carbon materials. In our previous paper, void-defect on graphene-nanoribbon show highly polarized spin configuration. In this paper, we studied cases for graphene molecules by quantum theory, by astronomical observation and by laboratory experiment. Model molecules for the density functional theory are graphene molecules of C23 and C53 induced by a void-defect. They have carbon pentagon ring within a hexagon network. Single void has three radical carbons, holding six spins. Those spins make several spin-states, which affects to molecular structure and molecular vibration, finally to infrared spectrum. The stable spin state was triplet, not singlet. This suggests magnetic pure carbon molecule. It was a surprise that those molecules show close infrared spectrum with astronomically observed one, especially observed on carbon rich planetary nebulae. We could assign major band at 18.9 micrometer, and sub-bands at 6.6, 7.0, 7.6, 8.1, 8.5, 9.0 and 17.4 micrometer. Also, calculated spectrum roughly coincides with that of laboratory experiment by the laser-induced carbon plasma, which is an analogy of cosmic carbon creation in interstellar space.

astro-ph.GA↗

arXiv2020

Graphene Molecules Contributing to the Infrared Bands of Carbon Rich Planetary Nebulae

It is well known since 2010 that fullerene C60 is widespread through the interstellar space. Also, it is well known that graphene is a source material for synthesizing fullerene. Here, we simply assume the occurrence of graphene in space. Infrared spectra of graphene molecules are calculated to compare both to astronomical observational spectra and to laboratory experimental one. Model molecules for DFT calculation are selected by one astronomical assumption, that is, single void in charge neutral graphene of C13, C24 and C54, resulting C12, C23 and C53. They have a carbon pentagon ring within a hexagon network. Different void positions are classified as different species. Single void is surrounded by 3 radical carbons, holding 6 spins. Spin state affects molecular configuration and vibrational spectrum. It was a surprise that the triplet state is stable than the singlet. Most of charge neutral and triplet spin state species show closely resembling spectra with observed one of carbon rich planetary nebulae Tc1 and Lin49. We could assign major bands at 18.9 micrometer, and sub-bands at 6.6, 7.0, 7.6, 8.1, 8.5, 9.0 and 17.4 micrometer. It is interesting that those graphene species were also assigned in the laboratory experiments on laser-induced carbon plasma, which are analogies of carbon cluster creation in space. The conclusion is that graphene molecules could potentially contribute to the infrared emission bands of carbon-rich planetary nebulae.

astro-ph.GA↗

arXiv2019

Graphene Molecule Compared With Fullerene C60 As Circumstellar Carbon Dust Of Planetary Nebula

It had been understood that astronomically observed infrared spectrum of carbon rich planetary nebula as like Tc 1 and Lin 49 comes from fullerene (C60). Also, it is well known that graphene is a raw material for synthesizing fullerene. This study seeks some capability of graphene based on the quantum-chemical DFT calculation. It was demonstrated that graphene plays major role rather than fullerene. We applied two astrophysical conditions, which are void creation by high speed proton and photo-ionization by the central star. Model molecule was ionized void-graphene (C23) having one carbon pentagon combined with hexagons. By molecular vibrational analysis, we could reproduce six major bands from 6 to 9 micrometer, large peak at 12.8, and largest peak at 19.0. Also, many minor bands could be reproduced from 6 to 38 micrometer. Also, deeply void induced molecules (C22) and (C21) could support observed bands.

astro-ph.GA↗

arXiv2018

Astronomical Infrared Spectrum of Planetary Nebula Lin49 and Tc1 Identified by Ionized Polycyclic-Pure-Carbon C23 and C60

Astronomical dust molecule of carbon-rich nebula-Lin49 and nebula-Tc1 could be identified to be polycyclic-pure-carbon C23 by the quantum-chemical calculation. Two driving forces were assumed. One is high speed proton attack on coronene-C24H12, which created void-induced C23H12. Another is high energy photon irradiation, which brought deep photo-ionization and finally caused dehydrogenation to be C23. Infrared spectrum calculation show that a set of ionized C23 (neutral, mono, and di-cation) could reproduce observed many peaks of 28 bands at wavelength from 6 to 38 micrometer. Previously predicted neutral fullerene-C60 could partially reproduce observed spectrum by 5 bands. Also, we tried calculation on ionized-C60, which show fairly good coincidence with observed 10 bands

astro-ph.GA↗

arXiv2018

Astronomical Creation of Cyclic-C3H2 and Chain-C3 Due to Interstellar Deep Photoionization

Astronomical evolution mechanism of small size polycyclic aromatic hydrocarbon (PAH) was analyzed using the first principles quantum-chemical calculation. Starting model molecule was benzene (C6H6), which would be transformed to (C5H5) due to carbon void created by interstellar high speed proton attack. In a protoplanetary disk around a young star, molecules would be illuminated by high energy photon and ionized to be cationic-(C5H5). Calculation shows that from neutral to tri-cation, molecule keeps original configuration. At a step of sixth cation, there occurs surprising creation of cyclic-C3H2, which is the smallest PAH. Astronomical cyclic-C3H2 had been identified by radio astronomy. Deep photoionization of cyclic-C3H2 brings successive molecular change. Neutral and mono-cation keep cyclic configuration. At a step of di-cation, molecule was transformed to aliphatic chain-C3H2. Finally, chain-C3H2 was decomposed to pure carbon chain-C3 and two hydrogen atoms. Calculated infrared spectrum of those molecules was applied to observed spectrum of Herbig Ae young stars. Observed infrared spectrum could be partially explained by small molecules. Meanwhile, excellent coincidence was obtained by applying a larger molecules as like (C23H12)2+ or (C12H8)2+. Infrared observation is suitable for larger molecules and radio astronomy for smaller asymmetric molecules. It should be noted that these molecules could be identified in a natural way introducing two astronomical phenomena, that is, void-induced molecular deformation and deep photoionization.

astro-ph.GA↗

arXiv2018

Astronomical Quantum-chemical Origin of Ubiquitously Observed Interstellar Infrared Spectrum due to Polycyclic Aromatic Hydrocarbon

Interstellar infrared observation shows featured spectrum due to polycyclic aromatic hydrocarbon (PAH)at wavelength 3.3,6.2,7.6,7.8,8.6,and 11.3 micrometer,which are ubiquitously observed in many astronomical dust clouds and galaxies. Our previous first principles calculation revieled that viod induced coronene (C23H12)2+ and circumcoronene (C53H18)1+ could reproduce such spectrum very well. In this study, quantum-mechanic origin was studied through atomic configuration change and atomic vibration mode analysis. By a high speed particle attack, carbon void would be introduced in PAH. Molecular configuration was deformed by the Jahn-Teller quantum effect. Carbon SP3 local bond was created among SP2 graphene like carbon network. Also, carbon tetrahedron local structure was created. Such peculiar structure is the quantum origin. Those metamorphosed molecules would be photo-ionized by the central star strong photon irradiation resulting cation molecules. Atomic vibration mode of cation molecule (C23H12)2+ was compared with that of neutral one (C23H12). At 3.3 micrometer, both molecules show show C-H stretching mode and give fairly large infrared intensity. At 6.2,7.6,7.8, and 8.6 micrometer bands, cation molecule show complex C-C stretching and shrinking mixing modes and remain large infrared emission. Whereas, neutral molecule gives harmonic motion, which cancelles each other resulting very small infrared intensity. At 11.3 micrometer, both neutral and cation molecules show C-H bending motion perpendicular to a molecular plane, which contributes to strong emission. Actual observed spectrum would be a sum of such quantum-mechanic origined molecules.

astro-ph.GA↗

arXiv2018

Astrochemical Evolution Step From Acenaphthylene C12H8 To Pure Carbon C12 Around A Herbig Ae Young Star

Astrochemical evolution step of polycyclic aromatic hydrocarbon (PAH) around a Herbig Ae young star was analyzed using the first principles quantum chemical calculation. For simplicity, model molecule was selected to be acenaphthylene (C12H8) with hydrocarbon one pentagon combined with two hexagons. In a protoplanetary disk, molecules are illuminated by high energy photon from the central star and ionized to be cation (C12H8)n+ . Calculation shows that from n=0 to 6, molecule keeps its polycyclic hydrocarbon configuration. Whereas, at ionization step n=7, there occurs dehydrogenation of (C12H8) to pure carbon (C12). Such polycyclic pure carbon (PPC) would be attacked again by photons. At a stage of eighth ionization (C12)8+, there occur decomposition to aliphatic carbon chains, C9, C2, and mono carbon C1. Infrared spectra (IR) of those steps were calculated to identify observed spectra . Carrier molecules of Herbig Ae star WW Vul and HD145263 were identified by a combination of (C12H8)2+ and (C12H8)1+. Also, IR of HD37357 could be explained by (C12H8)2+, (C12H8)3+, and (C12H8)1+. Pure carbon molecules play an important role in many stars. IR of HD37258 was analyzed by a mixture of pure carbon (C12)2+, hydrocarbon (C12H8)2+ and neutral (C12H8)0+. Also, complex spectrum of HD38120 was analyzed by (C12)2+, (C12H8)2+ and (C12H8)3+. Acenaphthylene related molecules are just a typical example. We should apply various size molecules to understand total view around a new born star.

astro-ph.SR↗

arXiv2018

Analyzing interstellar infrared spectrum by circumcoronene (C54H18) related molecules

It is very important to identify carrier molecules of astronomical interstellar infrared spectrum (IR) to understand chemical evolution step of polycyclic aromatic hydrocarbon (PAH) in the universe. In our previous study, it was suggested that coronene (C24H12) related PAH could reproduce such IR by the first principles quantum chemical calculation. In this paper, PAH candidates were enhanced to circumcoronene (C54H18) related molecules. Well known PAH oriented wavelength of 6.2, 7.7, 8.6, 11.3, and 12.7 micrometer were reproduced well by a void induced mono-cation (C53H18) having hydrocarbon two pentagons combined with 17 hexagons. Typical astronomical object are the red rectangle nebula and NGC6946, which is categorized as Type-B sectrum. Neutral circumcoronene show very strong IR peak at 11.1 micrometer, which is noted as Type-A spectrum observed in NGC1316 and NGC4589. Ubiquitously well observed spectrum was noted as Type-C, which could be explained by a suitable combination of Type-B and Type-A. Type-C objects are NGC7023, NGC2023 and so many. It should be noted that a dehydrogenated pure carbon mono-cation molecule (C53) show IR peaks at 6.3, 7.8, 8.5 micrometer, but no peak at 11.3 micrometer, which newly defined as Type-E. Such a strange characteristic can contribute to explain IR intensity ratio. Observed intensity ratio between peaks of 6.2, 7.7, 8.6, 11.3, and 12.7 micrometer each other were compared with above calculated IR intensities. Major intensity ratio was well reproduced by Type-B molecules. Variation of observed intensity ratio could be explained by a mixture degree between Type-B and Type-A, and also a mixture degree between Type-B and Type-E.

astro-ph.GA↗

arXiv2017

Herbig Ae Young Star's Infrared Spectrum Identified By Hydrocarbon Pentagon-Hexagon Combined Molecules

Infrared spectrum (IR) of Herbig Ae young stars was reproduced and classified by hydrocarbon pentagon-hexagon combined molecules by the quantum chemical calculation. Observed IR list by B. Acke et al. was categorized to four classes. Among 53 Herbig Ae stars, 26 samples show featured IR pattern named Type-D, which shows common IR peaks at 6.2, 8.3, 9.2, 10.0, 11.3, 12.1, and 14.0 micrometer. Typical star is HD144432. Calculation on di-cation molecule (C12H8)2+ having hydrocarbon one pentagon and two hexagons shows best coincidence at 6.1, 8.2, 9.2, 9.9, 11.3, 12.2, and 14.1 micrometer. There are some variation in Type-D. Spectrum of HD37357 was explained by a mixture with di-cation (C12H8)2+ and tri-cation (C12H8)3+. Ubiquitously observed spectrum Type-B was observed in 12 samples of Acke's list. In case of HD85567, observed 16 peaks were precisely reproduced by a single molecule (C23H12)2+. There is a mixture case with Type-B and Type-D. Typical example was HD142527. In this study, we could identify hidden carrier molecules for all types of IR in Herbig Ae stars.

astro-ph.GA↗

arXiv2017

Categorize Interstellar Infrared Spectrum by Polycyclic Pure-Carbon-Molecule and Hydrocarbon-Molecule

By applying quantum chemical calculation, interstellar infrared spectrum was categorized to three classes. Type-A show unusual feature of strong peaks at 11.3,12.9, and 14.0 micrometer. Usually observed 6.2, 7.7, and 8.6 micrometer bands are weak or not recognized. Typical examples are NGC1316 and NGC4589. Such spectrum could be identified for the first time by pure carbon molecule (C23)2+ (dication) having two carbon pentagons combined with five hexagons. Calculated spectrum coincided well at 11.3, 13.0, and 14.0 micrometer. Also we could find more coincidence at 5.2, 5.6, 7.6, 8.8,10.6,15.7 and 17.2 micrometer. Type-B is ubiquitously observed IR, but show medium strength at 11.3 micrometer. Examples are NGC6946 and the red triangle nebula. Coronene modified PAH (C23H12)2+ show best coincidence for both wavelength and strength. Type-C is usualy observed one featuring very strong peak at 11.3 micrometer. Examples are NGC7023, NGC2023 and M17SW. One capable expanation of large 11.3 micrometer band is a mixture of Type-A and Type-B. Combination of polycyclic pure-carbon-molecule and hydrocarbon-molecule may give a variety of IR spectrum.

astro-ph.GA↗

arXiv2017

Galaxy Scale Interstellar Infrared Spectrum Reproduced By A Hydrocarbon Pentagon-Hexagon Combined Molecule

Interstellar dust shows ubiquitous interstellar infrared spectrum (IR) due to polycyclic aromatic hydrocarbon (PAH). By our previous quantum chemistry calculation, it was suggested that a molecule group having hydrocarbon pentagon-hexagon combined skeleton could reproduce observed IR of dust clouds in Milky Way galaxy. This paper extends to other many galaxies. Typical galaxies are NGC6946 and M83. Those infrared spectrum were compared with that of a model molecule (C23H12)2+ having hydrocarbon two pentagons combined with five hexagons. Observed major infrared bands of 6.2, 7.7, 8.6, and 11.3 micrometer were successfully reproduced as 6.4, 7.7, 8.5, and 11.2 micrometer. Even observed weaker bands of 12.0, 12.7, 14.2 micrometer were predicted well by computed bands as 12.0, 12.6, and 13.9 micrometer. IR intensity ratio was compared to check theoretical validity. Calculated intensity ratio between 7.7 versus 11.3 micrometer (PAH7.7/11.3) was 4.0, whereas observed ratio was in a range of 2~6, also calculated PAH6.2/11.3 was 1.4 for observed range of 0.9~2.6. Especially, every calculated ratio was so close to that of M83 arm region. It should be noted that both calculated wavelength and intensity could reproduce observed galaxy scale infrared spectrum. Hydrocarbon pentagon-hexagon molecule would be general carrier in many galaxies including Milky Way.

astro-ph.GA↗