J/A+A/579/A46 Mono-^13^C acetaldehydes mm/submm wave spectra (Margules+, 2015) ================================================================================ Millimeter and submillimeter wave spectra of mono-13C acetaldehydes. Margules L., Motiyenko R.A., Ilyushin V.V., Guillemin J.-C. =2015A&A...579A..46M ================================================================================ ADC_Keywords: Atomic physics ; Spectra, millimetric/submm Keywords: ISM: molecules - methods: laboratory: molecular - submillimeter: ISM - molecular data - line: identification Abstract: The acetaldehyde molecule is ubiquitous in the interstellar medium of our galaxy, and due to its dense and complex spectrum, large dipole moment, and several low-lying torsional states, acetaldehyde is considered to be a "weed" molecule for radio astronomy observations. Mono-^13^C acetaldehydes ^13^CH_3_CHO and CH_3_^13^CHO are likely to be identified in astronomical surveys, such as those available with the very sensitive ALMA telescope. Laboratory measurements and analysis of the millimeter and submillimeter-wave spectra are the prerequisites for the successful radioastronomical search for the new interstellar molecular species, as well as for new isotopologs of already detected interstellar molecules. In this context, to provide reliable predictions of ^13^CH_3_CHO and CH_3_^13^CHO spectra in millimeter and submillimeter wave ranges, we study rotational spectra of these species in the frequency range from 50 to 945GHz. The spectra of mono-^13^C acetaldehydes were recorded using the spectrometer based on Schottky-diode frequency-multiplication chains in the Lille laboratory. The rotational spectra of ^13^CH_3_CHO and CH_3_^13^CHO molecules were analyzed using the Rho axis method. Description: This paper is a continuation of a series of studies conducted in PhLAM Lille (France) that are devoted to the investigations of the spectra of different isotopic species of astrophysical molecules. We present a new study of the ^13^CH_3_CHO and CH_3_^13^CHO spectra with measurements and analysis extended up to 945GHz. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table3.dat 80 7693 Assignments, measured transition frequencies, and residuals from the global fit of the microwave, millimeter-wave and submillimeter-wave vt=0,1,2 data for ^13^C acetaldehyde ^13^CH_3_CHO table4.dat 80 7275 Assignments, measured transition frequencies, and residuals from the global fit of the microwave, millimeter-wave and submillimeter-wave vt=0,1,2 data for ^13^C acetaldehyde CH_3_^13^CHO table5a.dat 33 30 Torsion-rotation part Qrt(T) of the total internal partition function Q(T)=Qv(T)*Qrt(T), calculated from first principles using the parameter set of Table 1 for ^13^C acetaldehyde ^13^CH_3_CHO. table5.dat 77 28789 A list of calculated positions and assignments of A-A and E-E transitions in the vt=0,1 torsional states of ^13^C acetaldehyde ^13^CH_3_CHO up to J=65 in the 1-1000GHz frequency range. table6a.dat 33 30 Torsion-rotation part Qrt(T) of the total internal partition function Q(T)=Qv(T)*Qrt(T), calculated from first principles using the parameter set of Table 1 for ^13^C acetaldehyde CH_3_^13^CHO table6.dat 77 28026 A list of calculated positions and assignments of A-A and E-E transitions in the vt=0,1 torsional states of ^13^C acetaldehyde CH_3_^13^CHO up to J=65 in the 1-1000GHz frequency range -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 A2 --- Sy1 Upper level symmetry in the G6 group: E, A1 or A2 5 I1 --- vt1 [0/2] Upper level torsional quantum number 8- 9 I2 --- J1 [1/60] Upper level asymmetric top rotational quantum number 12- 13 I2 --- Ka1 [0/22] Upper level asymmetric top rotational quantum number 16- 17 I2 --- Kc1 [0/55] Upper level asymmetric top rotational quantum number 22- 23 A2 --- Sy0 Lower level symmetry in the G6 group: E, A1 or A2 26 I1 --- vt0 [0/2] Lower level torsional quantum number 29- 30 I2 --- J0 [0/60] Lower level asymmetric top rotational quantum number 33- 34 I2 --- Ka0 [0/22] Lower level asymmetric top rotational quantum number 37- 38 I2 --- Kc0 [0/56] Lower level asymmetric top rotational quantum number 40- 50 F11.4 MHz Pos [9513/944843] Measured line position 52- 57 F6.4 MHz e_Pos [0.03/4] Uncertainty of Pos 59- 65 F7.4 MHz O-C [-1.1/9.4] Residuals from the global fit 67- 70 A4 --- Ref Source of data (1) 72 A1 --- Blend [b] b for blended lines 74- 80 F7.4 MHz Delta [-0.4/0.3]? Differences between the intensity-weighted average of calculated (but experimentally unresolved) transition wavenumbers (or frequencies in case of microwave data) and the observed position of the cluster of blended lines -------------------------------------------------------------------------------- Note (1): References (unlabeled data are from the present work): KLW = R.W. Kilb, C.C. Lin, E.B. Wilson, 1957, The Journal of Chemical Physics Vol. 26, #6, pp. 1695-1703 KLW* = one measured line from Kilb et al. 1957 labeled by '*' was excluded from the fit. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5a.dat table6a.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 K T [10/300] Temperature (1) 5- 13 F9.3 --- Qrt(A+E) A+E parts of the torsion-rotation part of partition function 15- 23 F9.4 --- Qrt(A) ? A part of the torsion-rotation part of partition function 25- 33 F9.4 --- Qrt(E) ? E part of the torsion-rotation part of partition function -------------------------------------------------------------------------------- Note (1): For the temperatures below 100K the separate A and E parts of the torsion-rotation part of partition function are given, where the A and E type levels are treated as the independent subsets of energy levels. The vibrational part Qv(T) (omitting the torsional vibration since it is taken into account in Qrt) may be estimated in the harmonic approximation using the vibrational frequencies reported for the parent species of acetaldehyde by T. Schimanouchi, Tables of Molecular Vibrational Frequencies, Vol. I: consolidated (National Bureau of Standards, Washington, DC, 1972), pp. 1-160. In the calculation the states up to J=100 and vt=8 were included. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 A2 --- Sy1 Upper level symmetry in the G6 group: E, A1 or A2 5 I1 --- vt1 [0/1] Upper level torsional quantum number 8- 9 I2 --- J1 [1/65] Upper level asymmetric top rotational quantum number 12- 13 I2 --- Ka1 [0/25] Upper level asymmetric top rotational quantum number 16- 17 I2 --- Kc1 [0/61] Upper level asymmetric top rotational quantum number 22- 23 A2 --- Sy0 Lower level symmetry in the G6 group: E, A1 or A2 26 I1 --- vt0 [0/1] Lower level torsional quantum number 29- 30 I2 --- J0 [0/65] Lower level asymmetric top rotational quantum number 33- 34 I2 --- Ka0 [0/25] Lower level asymmetric top rotational quantum number 37- 38 I2 --- Kc0 [0/62] Lower level asymmetric top rotational quantum number 40- 50 F11.4 MHz Pos [1001/999998] Measured line position (1) 52- 57 F6.4 MHz e_Pos [0.0001/0.1] Uncertainty of Pos 59- 67 F9.4 cm-1 E0 [0/1633] Lower state energy 69- 77 E9.4 D2 mu2S Dipole moment squared multiplied by the transition linestrength {mu}^2^S -------------------------------------------------------------------------------- Note (1): Note that only transitions with predicted uncertainties below 0.1MHz cutoff are given in the list. -------------------------------------------------------------------------------- Acknowledgements: Laurent Margules, laurent.margules(at)univ-lille1.fr ================================================================================ (End) Patricia Vannier [CDS] 30-Jun-2015