J/ApJ/768/81 Ethyl cyanide, CH_3_CH_2_CN, 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. =2013ApJ...768...81D ================================================================================ ADC_Keywords: Atomic physics Keywords: ISM: abundances; ISM: individual: Orion KL; ISM: molecules; line: identification; surveys Abstract: Ethyl cyanide, CH_3_CH_2_CN, 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, {nu}_12_ and {nu}_20_, 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 K_a_ 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 CH_3_CH_2_CN, 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) covering 26-200GHz was utilized. See section 2 for further explanations. Objects: -------------------------------------------------------------------- RA (ICRS) DE Designation(s) -------------------------------------------------------------------- 05 35 14.16 -05 22 21.5 NAME ORION-KL = NAME KLEINMANN-LOW NEB -------------------------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table4.dat 57 1342 Measured transitions of {nu}_20_ of ethyl cyanide sorted by frequency table5.dat 57 1342 Measured transitions of {nu}_20_ of ethyl cyanide table6.dat 57 1585 Measured transitions of {nu}_12_ of ethyl cyanide sorted by frequency table7.dat 57 1585 Measured transitions of {nu}_12_ of ethyl cyanide table8.dat 94 367 Detected lines of CH_3_CH_2_CN {nu}_13_=1/{nu}_21_=1 table9.dat 92 210 Detected lines of CH_3_CH_2_CN {nu}_20_ table10.dat 71 120 Detected lines of CH_3_CH_2_CN {nu}_12_ notes.dat 46 67 Notes -------------------------------------------------------------------------------- See also: J/A+A/559/A51 : HC_3_N 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 ^13^C-CH_3_CH_2_CN up to 1THz (Richard+, 2012) J/A+A/538/A119 : ^18^O-methyl formate (HCO^18^OCH_3_) spectrum (Tercero+ 2012) J/A+A/532/A32 : HCOOCH3 map of Orion-KL (Favre+, 2011) J/ApJ/714/1120 : Rotational spectrum and DCOOCH_3_ 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 HCOO^13^CH_3_ (Carvajal+, 2009) J/A+A/493/565 : Deuterated and ^15^N ethyl cyanides (Margules+, 2009) J/A+A/466/255 : Isotopic ethyl cyanide (Demyk+, 2007) J/ApJS/156/127 : 350{mu}m molecular line survey of Orion KL (Comito+, 2005) Byte-by-byte Description of file: table[46].dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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 {nu}_obs_ 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 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table[57].dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 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) -------------------------------------------------------------------------------- Note (1): Ordered by: * Type of branch: R and Q * Dipole moment: {mu}_a_ and {mu}_b_ * Quantum number K_a_ * Quantum number J -------------------------------------------------------------------------------- Byte-by-byte Description of file: table8.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- J The J level (1) 4- 5 I2 --- Ka The K_a_ state (1) 7- 8 I2 --- Kc The K_c_ state (1) 10- 11 I2 --- nu [0/5] The {nu} 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 {nu}' 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 T_MB_ 86- 89 F4.2 K.km/s Area ? Line area (G2) 91- 94 F4.2 K.km/s e_Area ? Error in Area (G2) -------------------------------------------------------------------------------- Note (1): The line transition in the format J_Ka,Kc,{nu}-J_K'a,K'c,{nu}'_. The {nu} quantum number defines A and E states: {nu}=0 is A for the bend and {nu}=3 is A for the torsion; {nu}=1 and 2 are E for the bend and {nu}=4 and 5 are E for the torsion. -------------------------------------------------------------------------------- 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 K_a_ state (1) 7- 8 I2 --- Kc The K_c_ state (1) 10- 11 I2 --- J' The J' level (1) 13- 14 I2 --- Ka' The K_a_' state (1) 16- 17 I2 --- Kc' The K_c_' 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) -------------------------------------------------------------------------------- Note (1): The line transition in the format J_Ka,Kc_-J_K'a,K'c_. -------------------------------------------------------------------------------- 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 K_a_ state (1) 7- 8 I2 --- Kc The K_c_ state (1) 10- 11 I2 --- J' The J' level (1) 13- 14 I2 --- Ka' The K_a_' state (1) 16- 17 I2 --- Kc' The K_c_' 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 {nu}_obs_ 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 -------------------------------------------------------------------------------- Note (1): The line transition in the format J_Ka,Kc_-J_K'a,K'c_. -------------------------------------------------------------------------------- Byte-by-byte Description of file: notes.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- Note Code of the note 4- 46 A43 --- Text Text of the note -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 25-Nov-2014