This is a list of molecules that have been the subject of unsuccessful astronomical searches in the interstellar or circumstellar media as well as claimed detections that have been soundly disconfirmed by subsequent work. A species may be detected in the future (i) in another source or (ii) with more sensitive observations or (iii) via different lines or (iv) in a different spectral regime. Note: Non-detections are ordered by the most recent unsuccessful search if multiple attempts have been reported.
Note: This is a work in progress and not a complete historical listing.
Submissions are welcome! Entries added in the last 1 or 2 months are highlighted in blue.
To be added to the table: Benzonitrile, Benzaldehyde, Toluene, Nitrobenzene, Cyclobutanone, Fulvene, Nitric Acid, MgO, ClO, CCl, Propylene Oxide, 2H-Azirine, o-Benzyne ...

YEAR
SPECIES
CITATION
SOURCE, DETECTION LIMIT, AND LINES
1973 FCN
cyanogen fluoride
Detection of new interstellar transitions of H, OCS, and H2CO and a search for interstellar fluorine
J. M. Hollis and B. L. Ulick. ApJ 214:699-702 (1973)
Orion A
NT < 1014 cm-2

J=2-1 (42216.64 MHz)
1973 CH3F
methyl fluoride
Detection of new interstellar transitions of H, OCS, and H2CO and a search for interstellar fluorine
J. M. Hollis and B. L. Ulick. ApJ 214:699-702 (1973)
Orion A
coincides with strong
H recombination line

JK=10-00 (51071.69 MHz)
1980 C4H5N
pyrrole
Search for interstellar pyrrole and furan
M. L. Kutner, D. E. Machnik, J. D. Tucker, and R. L. Dickman. ApJ 242:541-544 (1980)
A search for interstellar pyrrole: Evidence that rings are less abundant than chains
P. C. Myers, P. Thaddeus, and R. A. Linke. ApJ 241:155-157 (1980)
TMC-1
N(C4H5N) < 1012 cm-2

6 lines

Sgr B2
N(C4H5N) < 1-10 x 1013 cm-2

3 lines
1981 C3H4N2
imidazole
Searches for interstellar imidazole and cyanoform
W. M. Irvine, J. Ellder, Å. Hjalmarson, E. Kollberg, O. E. H. Rydbeck, G. O. Sørensen, B. Bak, and H. Svanholt. A&A 97:192-194 (1981)
Search for interstellar furan and imidazole
R. L. Dezafra, P. Thaddeus, M. Kutner, N. Scoville, P. M. Solomon, H. Weaver, and D. R. W. Williams. Astrophys Lett 10:1-3 (1972)
TMC-1, Ori A, etc.
N < 0.6-100 x 1013 cm-2

303 → 202 (33412.2 MHz)

Sgr A, Sgr B2
110-111 (4602.30 MHz)
1981 CH(CN)3
cyanoform
Searches for interstellar imidazole and cyanoform
W. M. Irvine, J. Ellder, Å. Hjalmarson, E. Kollberg, O. E. H. Rydbeck, G. O. Sørensen, B. Bak, and H. Svanholt. A&A 97:192-194 (1981)
TMC-1, Ori A, etc.
N < 2-10 x 1013 cm-2

J = 6 → 5 (34379 MHz)
1982 NaH
sodium hydride
A search for NaH in dense molecular clouds - evidence against formation on grains
R. L. Plambeck and N. R. Erickson. ApJ 262:606-610 (1982)
Orion A
[NaH]/[H2] < 10-11
(and 4 other sources)


J = 1-0 (289.864 GHz)
1994 SiH2
silylene
Submillimeter molecular line observations of IRC +10216: Searches for MgH, SiH2, and HCO+, and detection of hot HCN
L. W. Avery, M. B. Bell, C. T. Cunningham, P. A. Feldman, R. H., Harward, J. M. McLeod, H. E. Matthews, and J. D. Wade. ApJ 426:737-741 (1994)
IRC +10216
N(SiH2) ≤ 3.5 x 1015 cm-2

111-000 (353776 MHz
211-202 (305169 MHz
1998 MgH
magnesium monohydride
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Prior non-detection:
Submillimeter molecular line observations of IRC +10216: Searches for MgH, SiH2, and HCO+, and detection of hot HCN
L. W. Avery, M. B. Bell, C. T. Cunningham, P. A. Feldman, R. H., Harward, J. M. McLeod, H. E. Matthews, and J. D. Wade. ApJ 426:737-741 (1994)
Sgr B2(M), W49A(N)
[MgH]/[H2] ≤ 1 x 10-11

6 lines

IRC +10216
N(MgH) ≤ 6 x 1012 cm-2

(J,F)=(1/2,1→1/2,0) (343117.463 MHz)
(J,F)=(3/2,2→1/2,1) (344305.125 MHz)
1998 MgO
magnesium oxide
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Prior non-detection:
Searches for interstellar and circumstellar metal oxides and chlorides
T. J. Millar, J. Eldér, Å. Hjalmarson, and H Olofsson, AA 182:143-149 (1987)
Prior tentative detection:
Interstellar MgO
B. E. Turner and T. C. Steimle, ApJ 299:956-966 (1985)
Sgr B2(M), W49A(N)
[MgO]/[H2] ≤ 7.9 x 10-13

1-0 (34.298656 GHz)
3-2 (102.892416 GHz)
1998 MgOH
magnesium monohydroxide
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Sgr B2(M), W49A(N)
[MgOH]/[H2] ≤ 1.6 x 10-10

4 lines
1998 CaH
calcium monohydride
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Sgr B2(M), W49A(N)
[CaH]/[H2] ≤ 1.6 x 10-9

6 lines
1998 CaO
calcium oxide
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Sgr B2(M), W49A(N)
[CaO]/[H2] ≤ 2.0 x 10-12

3-2 (79.646084 GHz)
4-3 (106.192569 GHz)
1998 CaOH
calcium monohydroxide
A search for absorption of Mg and Ca compounds in molecular clouds towards Galactic continuum sources
S. Sakamoto, G. J. White, K. Kawaguchi, M. Ohishi, K. S. Usuda, and T. Hasegawa. MNRAS 301:872-880 (1998)
Sgr B2(M), W49A(N)
[CaOH]/[H2] ≤ 2.5 x 10-10

4 lines
2001 C4H4O
furan

ASTROMOLECULE OF THE MONTH FOR AUG 2015
Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal
J. E. Dickens, W. M. Irvine, A. Nummelin, H. Møllendal, S. Saito, S. Thorwirth, and Å Hjalmarson. Spectrochimica Acta A 57:643-660 (2001)
Search for interstellar pyrrole and furan
M. L. Kutner, D. E. Machnik, J. D. Tucker, and R. L. Dickman. ApJ 242:541-544 (1980)
Search for interstellar furan and imidazole
R. L. Dezafra, P. Thaddeus, M. Kutner, N. Scoville, P. M. Solomon, H. Weaver, and D. R. W. Williams. Astrophys Lett 10:1-3 (1972)
Various Sources
N(C4H4O) < 1014 cm-2

6 lines
2001 NH2SH
thiohydroxylamine
Searches for new interstellar molecules, including a tentative detection of aziridine and a possible detection of propenal
J. E. Dickens, W. M. Irvine, A. Nummelin, H. Møllendal, S. Saito, S. Thorwirth, and Å Hjalmarson. Spectrochimica Acta A 57:643-660 (2001)
Various Sources
N(NH2SH) < 2-8 x 1013 cm-2

31,3-21,2
2003 NH2CH2COOH
glycine

ASTROMOLECULE OF THE MONTH FOR SEP 2003
A rigorous attempt to verify interstellar glycine
L. E. Snyder, F. J. Lovas, J. M. Hollis, D. N. Friedel, P. R. Jewell, A. Remijan, V. V. Ilyushin, E. A. Alekseev, and S. F. Dyubko. ApJ 619:914-930 (2005)
A search for biomolecules in Sagittarius B2 (LMH) with the Australia Telescope Compact Array
P. A. Jones, M. R. Cunningham, P. D. Godfrey, and D. M. Cragg, MNRAS 374:579-589 (2007)
A search for propylene oxide and glycine in Sagittarius B2 (LMH) and Orion
M. R. Cunningham and 19 co-workers. MNRAS 376:1201-1210 (2007)
Discomfirmed detection:
Interstellar glycine
Y.-J. Kuan, S. B. Charnley, H.-C. Huang, W.-L. Tseng, and Z. Kisiel. ApJ 593:848-867 (2003)
Sgr B2(N-LMH), Orion KL, W51 e1/e2

27 mm-wave lines
2004 HC4N
(bent)
Detection of the Linear Radical HC4N in IRC +10216
J. Cernicharo, M. Guélin, and J. R. Pardo. ApJ 625:L145-L148 (2004)
IRC +10216
N(X) < 3 x 1012 cm-2

(lines not provided)
2004 HC4N
(ringed)
Detection of the Linear Radical HC4N in IRC +10216
J. Cernicharo, M. Guélin, and J. R. Pardo. ApJ 625:L145-L148 (2004)
IRC +10216
N(X) < 3 x 1012 cm-2

(lines not provided)
2005 C4H4N2
pyrimidine

ASTROMOLECULE OF THE MONTH FOR AUG 2014
Astronomical searches for nitrogen heterocycles
S. B. Charnley, Y.-J. Kuan, H.-C. Huang, O. Botta, H. M. Butner, N. Cox, D. Despois, P. Ehrenfreund, Z. Kisiel, Y.-Y. Lee, A. J. Markwick, Z. Peeters, and S. D. Rodgers. Adv Space Res 36:137-145 (2005)
A search for interstellar pyrimidine
Y.-J. Kuan, C.-H. Yan, S. B. Charnley, Z. Kisiel, P. Ehrenfreund, and H.-C. Huang. MNRAS 345:650-565 (2003)
Search for interstellar acrylonitrile, pyrimidine, and pyridine
M. N. Simon and M. Simon. ApJ 184:757-761 (1973)
CRL 618, IRC +10216

2 lines

Sgr B2(N), Orion KL, W51 e1/e2
N(Pyrimidine) < 1-3 x 1014 cm-2

many possible lines

Orion, Sgr B2

707-618 (46.266 GHz)
2005 C5H5N
pyridine
Astronomical searches for nitrogen heterocycles
S. B. Charnley, Y.-J. Kuan, H.-C. Huang, O. Botta, H. M. Butner, N. Cox, D. Despois, P. Ehrenfreund, Z. Kisiel, Y.-Y. Lee, A. J. Markwick, Z. Peeters, and S. D. Rodgers. Adv Space Res 36:137-145 (2005)
Search for Interstellar Acrylonitrile, Pyrimidine, and Pyridine
M. N. Simon and M. Simon. ApJ 184:757-761 (1973)
A search for interstellar molecular lines in the frequency range 8.6 to 9.2 GHz
R. A. Batchelor, J. W. Brooks, P. D. Godfrey, and R. D. Brown. Aus J Phys 26:557-560 (1973)
IRC +10216, CRL 618
N(Pyridine): various, < 1012 cm-2

8 doubtlets, a-type, J < 25

Orion, Sgr B2

707-608 (44.390 GHz)

Orion A, Sgr B2, Sgr(NH3)A

101-000 F(1-1) (8.76284 GHz)
101-000 F(2-1) (8.76429 GHz)
101-000 F(0-1) (8.76648 GHz)
2005 C9H7N
quinoline
Astronomical searches for nitrogen heterocycles
S. B. Charnley, Y.-J. Kuan, H.-C. Huang, O. Botta, H. M. Butner, N. Cox, D. Despois, P. Ehrenfreund, Z. Kisiel, Y.-Y. Lee, A. J. Markwick, Z. Peeters, and S. D. Rodgers. Adv Space Res 36:137-145 (2005)
IRC +10216, CRL 618, CRL 2688
N(Quin): various, < 1013 cm-2

various b-type doublets
2005 C9H7N
isoquinoline
Astronomical searches for nitrogen heterocycles
S. B. Charnley, Y.-J. Kuan, H.-C. Huang, O. Botta, H. M. Butner, N. Cox, D. Despois, P. Ehrenfreund, Z. Kisiel, Y.-Y. Lee, A. J. Markwick, Z. Peeters, and S. D. Rodgers. Adv Space Res 36:137-145 (2005)
IRC +10216, CRL 618, CRL 2688
N(Isoquin): various, < 1013 cm-2

a- and b-type quadruplets, J ≤ 73
2011 HeH+
helium hydride ion
ASTROMOLECULE OF THE MONTH FOR JAN 2016
A search for HeH+ and CH in a high-redshift quasi-stellar object
I. Zinchenko, V. Dubrovich, and C. Henkel. MNRAS 415:L76-L80 (2011)
An ISO Long Wavelength Spectrometer detection of CH in NGC 7027 and an HeH+ upper limit X.-W. Liu, M. J. Barlow, A. Dalgarno, J. Tennyson, T. Lim, B. M. Swinyard, J. Cernicharo, P. Cox, J.-P. Baluteau, D. Péquignot, Nguyen-Q-Rieu, R. J. Emery, and P. E. Clegg. MNRAS 290:L71-L75
SDSS J114816.64+525150.3
(quasar)


J = 1 - 0 (2010.183873 GHz)
NGC 7027
(planetary nebula)


J = 1 - 0 (149.14 μm)
2012 CH3CH(NH2)CN
2-aminopropionitrile
Rotational spectrum of a chiral amino acid precursor, 2-aminopropionitrile, and searches for it in Sagittarius B2(N)
H. Møllendal, L., Margulès, A. Belloche, R. A., Motiyenko, A. Konovalov, K. M. Menten, and J. C. Guillemin. A&A 538:A51 (2012)
Sgr B2(N)
N(X) < 1.7 x 1016 cm-2

many lines
2012 NH2OH
hydroxylamine

ASTROMOLECULE OF THE MONTH FOR FEB 2015
A Search for Hydroxylamine (NH2OH) toward Select Astronomical Sources
R. L. Pulliam, B. A. McGuire, and A. J. Remijan. ApJ 751:1 (2012)
IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M
N(NH2OH) < 2-8 x 1013 cm-2

14 lines
2013 CH2CHCH2NC
allyl isocyanide
The cm-, mm-, and sub-mm-wave Spectrum of Allyl Isocyanide and Radioastronomical Observations in Orion KL and the SgrB2 Line Surveys
I. Haykal, L. Margulès, T. R. Huet, R. A. Motyienko, P. Écija, E. J. Cocinero, F. Basterretxea, J. A. Fernández, F. Castaño, A. Lesarri, J. C. Guillemin, B. Tercero, and J. Cernicharo. ApJ 777:120 (2013)
Orion KL
N(CH2CHCH2NH) < 3.3 x 1014 cm-2

many lines
2014 NeH+
neonium

ASTROMOLECULE OF THE MONTH FOR FEB 2016
Ubiquitous argonium (ArH+) in the diffuse interstellar medium: A molecular tracer of almost purely atomic gas
P. Schilke, D. A. Neufeld, H. S. P. Müller, C. Comito, E. A. Bergin, D. C. Lis, M. Gerin, J. H. Black, M. Wolfire, N. Indriolo, J. C. Pearson, K. M. Menten, B. Winkel, Á. Sánchez-Monge, T. Möller, B. Godard, and E. Falgarone. A&A 566:A29 (2014)
Sgr B2(M),(N)
[NeH+]/[ArH+] < 0.1

1-0 (1039.3 GHz)
2014 NH+
imidogen cation
Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
C. M. Persson, M. Hajigholi, G. E. Hassel, A. O. H. Olofsson, J. H. Black, E. Herbst, H. S. P. Müller, J. Cernicharo, E. S. Wirström, M. Olberg, Å. Hjalmarson, D. C. Lis, H. M. Cuppen, M. Gerin, and K. M. Menten. A&A 567:A130 (2014)
SgrB2(M), W31C
[NH+]/[H2] < 2 x 10-12, 4 x 10-13

J=1.5-0.5 fs (1013, 1019 GHz)
2014 para-NH2
amino radial anion
Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)
C. M. Persson, M. Hajigholi, G. E. Hassel, A. O. H. Olofsson, J. H. Black, E. Herbst, H. S. P. Müller, J. Cernicharo, E. S. Wirström, M. Olberg, Å. Hjalmarson, D. C. Lis, H. M. Cuppen, M. Gerin, and K. M. Menten. A&A 567:A130 (2014)
SgrB2(M), W31C
N(NH2-) < 4 x 1011 cm-2

11,1 - 00,0 (943 GHz)
2015 H3S+
sulfonium

ASTROMOLECULE OF THE MONTH FOR MAY 2017
Sulphur-bearing molecules in diffuse molecular clouds: new results from SOFIA/GREAT and the IRAM 30 m telescope
D. A. Neufeld, B. Godard, M. Gerin, G. Pineau des Forêts, C. Bernier, E. Falgarone, U. U. Graf, R. Güsten, E. Herbst, P. Lesaffre, P. Schilke, P. Sonnentrucker, and H. Wiesemeyer. A&A 577:A49 (2015)
W31C, G29.96-0.02, G34.3+0.1, W49N, W41
τ(H3S+)/τ(H2S) < 10-2

10 - 00 (293.4572 GHz)
2015 C4H6O2
vinyl acetate
Laboratory millimeter wave spectrum and astronomical search for vinyl acetate
L. Kolesniková, I. Peña, J. L. Alonso, J. Cernicharo, B. Tercero, and I. Kleiner. A&A 577:A91 (2015)
Orion KL
N(vinyl acetate) < 4 x 1014 cm-2

Many lines
2016 H2S2
dihydrogen disulfide
The sulfur depletion problem: upper limits on the H2S2, HS2, and S2 gas-phase abundances toward the low-mass warm core IRAS 16293-2422
R. Martín-Doménech, I. Jiménez-Serra, G. M. Muñoz Caro, H. S. P. Müller, A. Occhiogrosso, L. Testi, P. M. Woods, and S. Viti. A&A 585:A112 (2016)
IRAS 16293-2422
[H2S2]/[H2] < 8.1 x 10-9

12 lines from 223-336 GHz
2016 HS2
monohydrogen disulfide
The sulfur depletion problem: upper limits on the H2S2, HS2, and S2 gas-phase abundances toward the low-mass warm core IRAS 16293-2422
R. Martín-Doménech, I. Jiménez-Serra, G. M. Muñoz Caro, H. S. P. Müller, A. Occhiogrosso, L. Testi, P. M. Woods, and S. Viti. A&A 585:A112 (2016)
IRAS 16293-2422
[HS2]/[H2] < 1.1 x 10-8

5 lines from 252-334 GHz
2016 S2
disulfur
The sulfur depletion problem: upper limits on the H2S2, HS2, and S2 gas-phase abundances toward the low-mass warm core IRAS 16293-2422
R. Martín-Doménech, I. Jiménez-Serra, G. M. Muñoz Caro, H. S. P. Müller, A. Occhiogrosso, L. Testi, P. M. Woods, and S. Viti. A&A 585:A112 (2016)
IRAS 16293-2422
[S2]/[H2] < 2.9 x 10-7

1110-99 (224.301 GHz)
1514-1313 (333.686 GHz)
2016 H2F+
fluoronium

ASTROMOLECULE OF THE MONTH FOR NOV 2016
Detection of HF Toward PKS 1830-211, Search for Interstellar H2F+, and Laboratory Study of H2F+ and H2Cl+ Dissociative Recombination
K. Kawaguchi, S. Muller, J. H. Black, T. Amano, F. Matsushima, R. Fujimori, Y. Okabayahsi, H. Nagahiro, Y. Miyamoto, and J. Tang. ApJ 822:115 (2016)
NGC 6334 I
[H2F+]/[H2Cl+] < 1/68
PKS 1830-211
[H2F+]/[HF] < 1/386

110-101 (760.929 GHz)
[redshifted to 403.5 GHz in PKS 1820-211]
212-101 (1850.082 GHz)
2016 CH3NCO
acetonitrile oxide
A rigorous detection of interstellar CH3NCO: An important missing species in astrochemical networks
J. Cernicharo, Z. Kisiel, B. Tercero, L. Kolesniková, I. R. Medvedev, A. López, S. Fortman, M. Winnewisser, F. C. de Lucia, J. L. Alonso, and J.-C. Guillemin. A&A 587:L4 (2016)
Orion
N(CH3NCO) < 6 x 1013 cm-2

???
2016 HSO
hydrogen sulfoxy
Laboratory measurements and astronomical search for the HSO radical
G. Cazzoli, V. Lattanzi, T. Kirsch, J. Gauss, B. Tercero, J. Cernicharo, and C. Puzzarini. A&A 591:A126 (2016)
Orion KL
N(HSO) < 1-4 x 1014 cm-2

Lines from 213.7-246.7 GHz

Sgr B2
N(HSO) < 1013 - 1016 cm-2

Lines from 7- 50 GHz
2016 CH3OCN
methyl cyanate
The millimeter wave spectrum of methyl cyanate: a laboratory study and astronomical search in space
L. Kolesniková, J. L. Alonso, C. Bermúdez, E. R. Alonso, B. Tercero, J. Cernicharo, and J.-C. Guillemin. A&A 591:A75 (2016)
A rigorous detection of interstellar CH3NCO: An important missing species in astrochemical networks
J. Cernicharo, Z. Kisiel, B. Tercero, L. Kolesniková, I. R. Medvedev, A. López, S. Fortman, M. Winnewisser, F. C. de Lucia, J. L. Alonso, and J.-C. Guillemin. A&A 587:L4 (2016)
Orion KL, Sgr B2(N), B1-b, TMC-1
various upper limits
300 lines from 130 to 250 GHz
Orion
N(CH3OCN) < 1 x 1014 cm-2

300 lines from 130 to 250 GHz
2016 NCCOCN
carbonyl cyanide
Millimeter wave spectra of carbonyl cyanide
S. B. Bteich, B. Tercero, J. Cernicharo, R. A. Motiyenko, L. Margulès, and J.-C. Guillemin. A&A 592:A43 (2016)
Orion KL
N(NCCOCN) < 5 x 1015 cm-2

Sgr B2(N)
N(NCCOCN) < 200 x 1015 cm-2

B1-b, TMC-1
various upper limits
1100 lines
2016 CH2CHOCHO
vinyl formate
Millimeter Wave Spectrum and Astronomical Search for Vinyl Formate
E. R. Alonso, L. Kolesniková, B. Tercero, C. Cabezas, J. L. Alonso, J. Cernicharo, and J.-C. Guillemin. ApJ 832:42 (2016)
Orion KL, Sgr B2(N), TMC-1 ...
Orion: N(VF) < 1.5 x 1016 cm-2

2600 transitions from 80-360 GHz
2016 HC11N
cyano-
pentaacetylene

ASTROMOLECULE OF THE MONTH FOR FEB 2014
Non-detection of HC11N towards TMC-1: constraining the chemistry of large carbon-chain molecules
R. A. Loomis, C. N. Shingledecker, G. Langston, B. A. McGuire, N. M. Dollhopf, A. M. Burkhardt, J. Corby, S. T. Booth, P. B. Carroll, B. Turner, and A. J. Remijan. MNRAS 463:4175 (2016)
Discomfirmed detection:
Detection of HC11N in the Cold Dust Cloud TMC-1
M. B. Bell, P. A. Feldman, M. J. Travers, M. C. McCarthy, C. A. Gottlieb, and P. Thaddeus, ApJ 483:L61-L64 (1997)
TMC-1
N(HC11N) < ~1-4 x 1011 cm-2

J = 38-37 (12848.7 MHz)
J = 39-38 (13186.9 MHz)
J = 40-39 (13525.0 MHz)
J = 41-40 (13863.1 MHz)
J = 42-41 (14201.2 MHz)
J = 43-42 (14539.3 MHz)

Click on the    link icon to see the NIST Webbook entry for a species (where available).

uv-vis (electronic)     mm/sub-mm (rotational)     infrared (vibrational)
Maintained by DE Woon
Updated 1 May 2017