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J/A+A/500/1109      Rotational spectrum of HCOO13CH3       (Carvajal+, 2009)

Rotational spectrum of 13C2-methyl formate (HCOO13CH3) and detection of the two 13C-methyl formate in Orion. Carvajal M., Margules L., Tercero B., Demyk K., Kleiner I., Guillemin J.C., Lattanzi V., Walters A., Demaison J., Wlodarczak G., Huet T.R., Mollendal H., Ilyushin V.V., Cernicharo J. <Astron. Astrophys. 500, 1109 (2009)> =2009A&A...500.1109C
ADC_Keywords: Interstellar medium ; Atomic physics ; Radio lines Keywords: line: identification - methods: data analysis - methods: laboratory - methods: observational - ISM: molecules - submillimeter Abstract: Laboratory measurements and analysis of the microwave and millimeter-wave spectra of potential interstellar molecules are a prerequisite for their subsequent identification by radioastronomical techniques. The spectral analysis provides spectroscopic parameters that are used in the assignment procedure of the laboratory spectra, and that also predict the frequencies of transitions not measured in the laboratory with a high degree of precision. An experimental laboratory study and its theoretical analysis is presented for 13C2-methyl formate (HCOO13CH3) allowing a search for this isotopologue in the Orion molecular cloud. The 13C1-methyl formate (H13COOCH3) molecule was also searched for in this interstellar cloud, using previously published spectroscopic data. Description: The experimental spectra of 13C2-methyl formate were recorded in the microwave and sub-mm energy ranges (4-20GHz, 8-80GHz, 150-700GHz). The spectra were analyzed using the Rho-Axis Method (RAM), which takes the CH3 internal rotation and the coupling between internal rotation and global rotation into account. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 102 934 *13C2-Methylformate HCOO13CH3 tablea2.dat 73 154 Emission lines of A-HCOO13CH3 (without high blend) present in the frequency range of the Orion KL survey tablea3.dat 73 113 Emission lines of E-HCOO13CH3 (without high blend) present in the frequency range of the Orion KL survey tablea4.dat 73 134 Emission lines of A-H13COOCH3 (without high blend) present in the frequency range of the Orion KL survey tablea5.dat 73 130 Emission lines of E-H13COOCH3 (without high blend) present in the frequency range of the Orion KL survey notes.dat 51 58 Notes
Note on tablea1.dat: Assignments, observed frequencies, calculated frequencies, residuals from the RAM fit, line strengths, and lower energy levels for 13C2-methyl formate (HCOO13CH3) microwave transitions from vt=0 state included in the fit with parameters of Table 2.
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1 I1 --- vt0 [0] Upper state vt (torsional) value (1) 3- 4 I2 --- J0 Upper state J quantum number value (1) 6 A1 --- n_Ka0 [*] * when two degenerate levels (1) 7 A1 --- --- [(] 8- 10 I3 --- Ka0 Upper state Ka quantum number value (1) 11 A1 --- --- [,] 13 I1 --- Ka0b ? Second value for Ka0 14 A1 --- --- [)] 15 A1 --- n_Kc0P0 [*] * when two degenerate levels (1) 16 A1 --- --- [(] 17- 19 A3 --- Kc0P0 Upper state KcP quantum number value (1) 20 A1 --- --- [,] 21- 23 A3 --- Kc0P0b Second value of Kc0P0 24 A1 --- --- [)] 26 I1 --- vt1 [0] Lower state vt (torsional) value (1) 28- 29 I2 --- J1 Lower state J value (1) 31 A1 --- n_Ka1 [*] * when two degenerate levels (1) 32 A1 --- --- [(] 33- 35 I3 --- Ka1 Lower state Ka quantum number value (1) 36 A1 --- --- [,] 37 I1 --- Ka1b ? Second value of Ka1 38 A1 --- --- [)] 39 A1 --- n_Kc1P1 [*] * when two degenerate levels (1) 40 A1 --- --- [(] 41- 43 A3 --- Kc1P1 Lower state KcP quantum number value (1) 44 A1 --- --- [,] 45- 47 A3 --- Kc1P1b Second value of Kc1P1 48 A1 --- --- [)] 50- 59 F10.3 MHz Freq Observed vt=0 microwave transitions (2) 61- 63 I3 kHz e_Freq rms uncertainty on Freq 65- 74 F10.3 MHz FreqC Calculated line frequency 76- 77 I2 kHz e_FreqC rms uncertainty on FreqC 79- 84 F6.3 MHz O-C Observed minus calculated frequencies value 86- 92 F7.3 D+2 S Calculated line strengths 94-102 F9.4 cm-1 Elow Lower state energy (3)
Note (1): Upper and lower state quantum numbers are indicated by 0 (') and 1 (") respectively. Torsion-rotation levels of A species have a "parity" label; levels of E species have a signed Ka value [Herbst et al. 1984]. 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 5kHz measurement uncertainty are MWFT lines (4-20GHz), the lines with 30, 100, 200kHz measurement uncertainty are Lille BWO lines (150-700GHz), the lines with 150 and 200kHz measurement uncertainty are Oslo lines (8-80GHz). Note (3): Referred to the J=Ka=0 A-species energy level taken as the zero of the energy (zero point torsional energy : 68.8326cm-1)
Byte-by-byte Description of file: tablea[2345].dat
Bytes Format Units Label Explanations
1- 19 A19 --- Trans Transition (JKa,Kc) 21- 30 F10.3 MHz Freq Calculated frequency 31 A1 --- r_Freq [as] References for Freq (1) 33- 38 F6.3 D+2 Sij Line strength 40- 47 F8.4 cm-1 Eu Energy of the upper level 49- 57 F9.2 MHz RestFreq ? Observed (centroid) rest frequencies assuming that the radial velocities relative to LSR are 7.5km/s 58 A1 --- n_RestFreq [b] b = blended with previous line 60- 64 F5.3 K Temp ?=- Observed temperature of main beam (at the peak of the line) 65- 67 A3 --- n_Temp Notes, in notes.dat file 69- 73 F5.3 K Tmean ?=- Main beam temperature obtained with the model
Note (1): References as follows: a = experimental frequency is available in the Table A1 s = experimental frequency is available (Willaert et al., 2006, J. Mol. Struct., 795, 4; Maeda et al. 2008, Ap&SS 175, 138).
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 2 A2 --- Note Note code 6- 51 A46 --- Text Text of the note
Acknowledgements: Miguel Carvajal,
(End) Patricia Vannier [CDS] 17-Apr-2009
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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