J/ApJ/768/81 Ethyl cyanide, CH3CH2CN, vibrational states (Daly+, 2013)
Laboratory characterization and astrophysical detection of vibrationally
excited states of ethyl cyanide.
Daly A.M., Bermudez C., Lopez A., Tercero B., Pearson J.C., Marcelino N.,
Alonso J.L., Cernicharo J.
<Astrophys. J., 768, 81 (2013)>
=2013ApJ...768...81D 2013ApJ...768...81D
ADC_Keywords: Atomic physics
Keywords: ISM: abundances; ISM: individual: Orion KL;
ISM: molecules; line: identification; surveys
Abstract:
Ethyl cyanide, CH3CH2CN, is an important interstellar molecule
with a very dense rotational-vibrational spectrum. On the basis of new
laboratory data in the range of 17-605GHz and ab initio calculations,
two new vibrational states, ν12 and ν20, have been detected
in molecular clouds of Orion. Laboratory data consist of Stark
spectroscopy (17-110GHz) and frequency-modulated spectrometers
(GEM laboratory in Valladolid: 17-170, 270-360GHz; Toyama: 26-200GHz;
Emory: 200-240GHz; Ohio State: 258-368GHz; and JPL: 270-318,
395-605GHz). More than 700 distinct lines of each species were
measured in J up to 71 and in Ka up to 25. The states were fitted
with Watson's S-reduction Hamiltonian. The two new states have been
identified in the interstellar medium toward the Orion Nebula
(Orion KL). The ground state, the isotopologues of CH3CH2CN, and
the vibrationally excited states have been fitted to obtain column
densities and to derive vibrational temperatures. All together, ethyl
cyanide is responsible for more than 2000 lines in the observed
frequency range of 80-280GHz.
Description:
The experiments performed in Valladolid with frequency modulation (FM)
from 110 to 170GHz and 240 to 360GHz were carried out in a static free
space glass cell with Teflon windows fitted with ports to evacuate and
maintain pressures of 20mTorr with a 2m length and 12cm diameter.
Additional measurements covering 270-318GHz and 395-605GHz were
performed at the Jet Propulsion Laboratory (JPL) and at the Ohio State
University with the FASSST spectrometer covering 268-368GHz. Some
additional spectra covering 200-240GHz were collected at Emory
University and (the study peak list of Fukuyama et al.
1996ApJS..104..329F 1996ApJS..104..329F) covering 26-200GHz was utilized.
See section 2 for further explanations.
Objects:
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RA (ICRS) DE Designation(s)
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05 35 14.16 -05 22 21.5 NAME ORION-KL = NAME KLEINMANN-LOW NEB
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 57 1342 Measured transitions of ν20 of ethyl cyanide
sorted by frequency
table5.dat 57 1342 Measured transitions of ν20 of ethyl cyanide
table6.dat 57 1585 Measured transitions of ν12 of ethyl cyanide
sorted by frequency
table7.dat 57 1585 Measured transitions of ν12 of ethyl cyanide
table8.dat 94 367 Detected lines of CH3CH2CN ν13=1/ν21=1
table9.dat 92 210 Detected lines of CH3CH2CN ν20
table10.dat 71 120 Detected lines of CH3CH2CN ν12
notes.dat 46 67 Notes
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See also:
J/A+A/559/A51 : HC3N in Orion KL (Esplugues+, 2013)
J/A+A/548/A71 : Spectroscopy and ISM detection of formamide (Motiyenko+, 2012)
J/A+A/543/A135 : New analysis of 13C-CH3CH2CN up to 1THz (Richard+, 2012)
J/A+A/538/A119 : 18O-methyl formate (HCO18OCH3) spectrum (Tercero+ 2012)
J/A+A/532/A32 : HCOOCH3 map of Orion-KL (Favre+, 2011)
J/ApJ/714/1120 : Rotational spectrum and DCOOCH3 in Orion (Margules+, 2010)
J/ApJ/714/476 : Complete spectrum of ethyl cyanide (Fortman+, 2010)
J/ApJS/184/133 : New ground-state measurements of ethyl cyanide (Brauer+, 2009)
J/A+A/500/1109 : Rotational spectrum of HCOO13CH3 (Carvajal+, 2009)
J/A+A/493/565 : Deuterated and 15N ethyl cyanides (Margules+, 2009)
J/A+A/466/255 : Isotopic ethyl cyanide (Demyk+, 2007)
J/ApJS/156/127 : 350µm molecular line survey of Orion KL (Comito+, 2005)
Byte-by-byte Description of file: table[46].dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- J' The J' level
4- 5 I2 --- K'a The K'a level
7- 8 I2 --- K'c The K'c level
10- 11 I2 --- J" The J" level
13- 14 I2 --- K"a The K"a level
16- 17 I2 --- K"c The K"c level
19- 28 F10.3 Hz nu [17393.3/604758] Observed frequency νobs
30- 35 F6.3 Hz O-C Difference between observed and
calculated frequencies
37- 40 F4.2 Hz e_nu [0.05/0.2] Error in nu
42 A1 --- f_nu [*] Indicates a non-fitted line
44- 46 A3 --- Blend [Yes ] Blended line?
48- 57 F10.3 Hz fPeak [44804.4/601388]? Weighted average peak frequency
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Byte-by-byte Description of file: table[57].dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- J' The J' level (1)
4- 5 I2 --- K'a The K'a level (1)
7- 8 I2 --- K'c The K'c level (1)
10- 11 I2 --- J" The J" level (1)
13- 14 I2 --- K"a The K"a level (1)
16- 17 I2 --- K"c The K"c level (1)
19- 28 F10.3 Hz nu [17393.3/604758] Observed frequency (1)
30- 35 F6.3 Hz O-C Difference between observed and
calculated frequencies (1)
37- 40 F4.2 Hz e_nu [0.05/0.2] Error in nu (1)
42 A1 --- f_nu [*] Indicates a non-fitted line (1)
44- 46 A3 --- Blend [Yes ] Blended line? (1)
48- 57 F10.3 Hz fPeak [44804/601388]? Weighted average peak frequency (1)
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Note (1): Ordered by:
* Type of branch: R and Q
* Dipole moment: µa and µb
* Quantum number Ka
* Quantum number J
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- J The J level (1)
4- 5 I2 --- Ka The Ka state (1)
7- 8 I2 --- Kc The Kc state (1)
10- 11 I2 --- nu [0/5] The ν state (1)
13- 14 I2 --- J' The J' level (1)
16- 17 I2 --- K'a The K'a state (1)
19- 20 I2 --- K'c The K'c state (1)
22 I1 --- nu' [0/5] The ν' state (1)
24- 33 F10.3 MHz nuP [80481.1/272019] Predicted laboratory frequency
35 A1 --- f_nuP [*] Indicates line blended with previous row
37- 41 F5.2 --- Sij [0.9/40.3] Line strength
43- 47 F5.1 K Eu [317.9/526] Upper level energy
49 A1 --- f_Eu [NW] Flag on Eu (G1)
51- 54 F4.2 km/s VLSR [0.7/8] Local Standard of Rest radial
velocity (G2)
56- 59 F4.2 km/s e_VLSR [0.08/1.3]? Error in VLSR (G2)
61- 67 A7 --- n_VLSR Reference(s) on VLSR (see notes.dat)
70- 74 F5.2 km/s Width ? Line width (G2)
76- 79 F4.2 km/s e_Width ? Error in Width (G2)
81- 84 F4.2 K TMB [0.08/4.3] Mean beam temperature TMB
86- 89 F4.2 K.km/s Area ? Line area (G2)
91- 94 F4.2 K.km/s e_Area ? Error in Area (G2)
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Note (1): The line transition in the format JKa,Kc,ν-JK'a,K'c,ν'_.
The ν quantum number defines A and E states: ν=0 is A for the
bend and ν=3 is A for the torsion; ν=1 and 2 are E for the bend
and ν=4 and 5 are E for the torsion.
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- J The J level (1)
4- 5 I2 --- Ka The Ka state (1)
7- 8 I2 --- Kc The Kc state (1)
10- 11 I2 --- J' The J' level (1)
13- 14 I2 --- Ka' The Ka' state (1)
16- 17 I2 --- Kc' The Kc' state (1)
19- 28 F10.3 MHz nuP [80470.3/276969.5] Predicted laboratory frequency
30 A1 --- f_nuP [*] Indicates line blended with previous row
32- 36 F5.2 --- Sij [3.5/32] Line strength
38- 42 F5.1 K Eu [564.8/889.4] Upper level energy
44 A1 --- f_Eu [NW] Flag on Eu (G1)
46- 49 F4.2 km/s VLSR [0.2/8] Local Standard of Rest radial
velocity (G2)
51- 54 F4.2 km/s e_VLSR [0.05/2]? Error in VLSR (G2)
56- 65 A10 --- n_VLSR Reference(s) on VLSR (see notes.dat file)
67- 71 F5.2 km/s Width ? Line width (G2)
73- 76 F4.2 km/s e_Width ? Error in Width (G2)
78- 81 F4.2 K TMB [0.02/1.6] Mean beam temperature
83- 87 F5.3 K.km/s Area ? Line area (G2)
89- 92 F4.2 K.km/s e_Area ? Error in Area (G2)
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Note (1): The line transition in the format JKa,Kc-JK'a,K'c.
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Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- J The J level (1)
4- 5 I2 --- Ka The Ka state (1)
7- 8 I2 --- Kc The Kc state (1)
10- 11 I2 --- J' The J' level (1)
13- 14 I2 --- Ka' The Ka' state (1)
16- 17 I2 --- Kc' The Kc' state (1)
19- 28 F10.3 MHz nuP [80288/278417.3] Predicted laboratory frequency
30 A1 --- f_nuP [*] Indicates line blended with previous row
32- 36 F5.2 --- Sij [1.8/30.7] Line strength
38- 43 F6.1 K Eu [799/1017.1] Upper level energy
45- 52 F8.1 MHz nuO [80290.1/278422] Observed frequency νobs
54- 57 A4 --- n_nuO Reference(s) on nuO (see notes.dat file)
59- 61 F3.1 km/s VLSR [0.5/9]? Local Standard of Rest radial velocity
63- 66 F4.2 K TMBo [0.01/0.5]? Observed mean beam temperature
68- 71 F4.2 K TMBm [0.01/0.4] Mean beam temperature from model
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Note (1): The line transition in the format JKa,Kc-JK'a,K'c.
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Note Code of the note
4- 46 A43 --- Text Text of the note
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Global notes:
Note (G1): Flag on Eu as follows:
N = Narrow component.
W = Wide component.
Note (G2): The observed parameters are shown when the line is not blended
with other molecule and no uncertainty is provided. Calculated
parameters have uncertainties and mean the line can not be fitted like
a gaussian or there is some contribution from other molecule.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 25-Nov-2014