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J/ApJ/714/1120    Rotational spectrum and DCOOCH3 in Orion   (Margules+, 2010)

Rotational spectrum and tentative detection of DCOOCH3-Methyl formate in Orion. Margules L., Huet T.R., Demaison J., Carvajal M., Kleiner I., Mollendal H., Tercero B., Marcelino N., Cernicharo J. <Astrophys. J., 714, 1120-1132 (2010)> =2010ApJ...714.1120M
ADC_Keywords: Interstellar medium ; Line Profiles ; Spectra, millimetric/submm Keywords: ISM: molecules - line: identification - methods: data analysis - methods: laboratory - methods: observational - submillimeter: ISM Abstract: New centimeter-wave (7-80GHz) and submillimeter-wave (580-661GHz) spectra of a deuterated species of methyl formate (DCOOCH3) have been measured. Transitions with a maximum value of J=64 and K=36 have been assigned and fitted together with previous measurements. The internal rotation of this compound was treated using the so-called rho axis method (RAM). A total of 1703 transitions were fitted using this method. Only 24 parameters were employed in the final fit, which has an rms deviation of 94.2kHz. The dipole moment and the nuclear quadrupole coupling constants of the deuterated species have also been obtained. This new study has permitted a tentative detection of DCOOCH3 in Orion with the IRAM 30m telescope based on the observation of more than 100 spectral features with low blending effects among the 400 lines expected in the observed frequency domain (for which over 300 are heavily blended with other species). These 100 transitions are above noise and confusion limited without heavy blending and cannot be assigned to any other species. Moreover, none of the strongest unblended transitions is missing. The derived source-averaged total column density for DCOOCH3 is 7.8x1014cm-2 and the DCOOCH3/HCOOCH3 column density ratio varies between 0.02 and 0.06 in the different cloud components of Orion. This value is consistent with the deuteration enhancement found for other species in this cloud. Description: The hyperfine structure of DCOOCH3 (O=CD-O-CH3) was observed using the new molecular beam Fourier transform microwave (FTMW) spectrometer of Lille. The rotational spectrum was studied in the range 7-80GHz using the Oslo Stark spectrometer. The submillimeter-wave measurements (580-661GHz) were performed in Lille with a source-modulated spectrometer using phase-stabilized backward wave oscillators (BWO) working in the frequency range 150-670GHz. For the tentative detection in Orion, the observations were carried out using the IRAM 30m radio telescope during 2004 September (3mm and 1.3mm), 2005 March (2mm), and 2005 April (3mm and 1.3mm). We have covered the total spectral range allowed by the 30m receivers. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 121 1574 Results of the global fit of ground torsionnal state of deuterated methyl formate (DCOOCH3)
See also: J/A+A/538/A119 : Spectrum of 18O-methyl formate (HCO18OCH3) (Tercero+ 2012) J/ApJS/190/315 : Rotational spectrum of H13COOCH3 (Carvajal+, 2010) J/A+A/500/1109 : Rotational spectrum of HCOO13CH3 (Carvajal+, 2009) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 5 I5 --- LNum [1/99926] Line number 7 I1 --- vt' [0] Upper vt quantum number (1) 9- 10 I2 --- J' [1/64] Upper J quantum number (1) 12- 13 A2 --- Ka'd [*(] indicates Ka' is degenerate (1) 14- 16 I3 --- Ka' [-36/35] Upper Ka quantum number (1) 17 A1 --- --- [,] in degenerate case (1) 18- 20 I3 --- Ka'2 ? 2nd Ka' number in case of degeneracy (1) 21 A1 --- --- [)] in degenerate case (1) 22- 23 A2 --- Kc'd [*(] indicates Kc' is degenerate (1) 24- 26 I3 --- Kc' [0/64] Upper Kc quantum number (1) 27 A1 --- P' [±] parity of upper state (1) 28 A1 --- --- [,] in degenerate case (1) 29- 31 I3 --- Kc'2 ? 2nd Kc' number in case of degeneracy (1) 32 A1 --- P'2 [±] second parity in case of degeneracy (1) 33 A1 --- --- [)] in degenerate case (1) 35 I1 --- vt" [0] Lower vt quantum number (1) 37- 38 I2 --- J" [0/63] Lower J quantum number (1) 40- 41 A2 --- Ka"d [*(] indicates Ka" is degenerate (1) 42- 44 I3 --- Ka" [-36/35] Lower Ka quantum number (1) 45 A1 --- --- [,] in degenerate case (1) 46- 48 I3 --- Ka"2 ? 2nd Ka" number in case of degeneracy (1) 49 A1 --- --- [)] in degenerate case (1) 50- 51 A2 --- Kc"d [*(] indicates Kc" is degenerate (1) 52- 54 I3 --- Kc" [0/63] Lower Kc quantum number (1) 55 A1 --- P" [±] parity of upper state (1) 56 A1 --- --- [,] in degenerate case (1) 57- 59 I3 --- Kc"2 ? 2nd Kc" number in case of degeneracy (1) 60 A1 --- P"2 [±] second parity in case of degeneracy (1) 61 A1 --- --- [)] in degenerate case (1) 63- 72 F10.3 MHz Freq.O Observed vt=0 microwave transition frequency 74- 76 I3 kHz e_Freq.O Uncertainty in Freq.O (2) 78- 87 F10.3 MHz Freq.C Calculated line frequency 89- 91 I3 kHz e_Freq.C Uncertainty in Freq.C 93- 98 F6.3 MHz O-C Observed - Calculated frequencies 100-106 F7.3 D+2 LStr Calculated line strength 108-116 F9.4 cm-1 Elow Lower energy (3) 118-121 A4 --- Obs Source (4)
Note (1): Torsion-rotation levels of A species have a "parity" label; levels of E species have a signed Ka value [Herbst et al. 1984JMoSp.108...42H]. Note that for degenerate transitions, only the sum of line strengths of the degenerate transitions for a given cluster is preserved. Therefore the degenerate clusters of transitions is represented by only one transition frequency accompanied by the sum of line strengths calculated for the cluster components. For those cases, instead of the usual label J, Ka, Kc , the cluster is represented by the rotational state designation J, * where the asterisk stands for the two degenerate levels with the same J, Kc but with different Ka quantum numbers, or with the same J, Ka but with different Kc quantum numbers. In the parentheses, for the A-species, the two different Ka (or Kc) levels and the parity quantum number '+' or '-' are indicated and means that those two levels are degenerate within the selected cutoff (0.005MHz). For the E-species, the parentheses contains + or -Ka (Kc) and it means that those two levels are degenerate within the same selected cutoff (0.005MHz). Note (2): Lines with 3 or 10kHz measurement uncertainty are FTMW lines (4-18GHz), the lines with 50, 100, or 200kHz measurement uncertainty are Lille BWO lines (150-700GHz), the lines with 150 and 200kHz measurement uncertainty are OSLO lines (7-80GHz) and the lines with a 80 or 200kHz uncertainty come from Oesterling et al. 1995JMoSp.172..469O. Note (3): Referred to the J=Ka=0 A-species energy level taken as the zero of the energy (zero point torsional energy : 66.0929cm-1) Note (4): Source of observation as follows: BWO = backward wave oscillators (Lille: submillimeter-wave spectrometer) CURL = Curl, R.F., Jr. 1959JChPh..30.1529C FTMW = Fourier transform microwave (FTMW) spectrometer (Lille) OEST = Oesterling et al. 1995JMoSp.172..469O OSLO = Stark centimeter wave spectrometer (Oslo)
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Apr-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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