Far-infrared spectra of dimethyl-ether and its 13C enriched isotopologues: The fundamental band of the C–O–C in plane bending mode, ν7

New Spectral Characterization of Dimethyl Ether Isotopologues CH3OCH3 and 13CH3OCH3 in the THz Region

“…Thus, the quoted uncertainties range from ±0.2cm −1 for isolated narrow bands up to±0.5cm −1 for broad, overlapped, or weak bands. As a representative check, the (001) bending energy levels, observed here at 412.5cm −1 for DME and 410.0cm −1 for 13 C-DME, are consistent within the experimental error with the more accurate values (412.350 and 409.993 cm −1 ) reported recently by Kutzer et al (2016).…”

“…To obtain the best fit parameters of the effective Hamiltonian, we started from the ab initio potential energy surfaces and the ab initio kinetic parameters calculated in our previous works on DME (Villa et al 2011) and 13 C-DME . Those ab initio calculations provided a reasonable description of the torsional features but failed to reproduce the bending fundamental ν 7 (421.64 cm −1 ab initio versus 412.35 cm −1 , as observed by Kutzer et al 2016). The ab initio Hamiltonian was then refined in this work following three steps: (i) the adjustment of the bending fundamental close to the experimental value, (ii) the reassignment of the two torsional fundamentals and their overtones according to the new Raman spectra, and (iii) the assignment of the other observed bands and the subsequent global fit of the Hamiltonian.…”

“…Two sets of Raman spectra of DME were recorded in this work: (i) at room temperature and (ii) jet cooled. The sample of DME was supplied by Praxair, with nominal purity of 99.8%, while that of 13 C-DME was synthesized in the University of Kassel, Germany (Kutzer et al 2016); the latter sample was distilled by liquid nitrogen to remove residual H 2 from the synthesis. Raman spectra of DME and of 13 C-DME were recorded at room temperature under static conditions (pressure 550 mbar and 380 mbar, respectively).…”

“…In addition to works prior to its detection in the ISM  (Taylor & Vidale 1957;Kasai & Myers 1959;Fateley & Miller 1962;Blukis et al 1963;Durig et al 1976;Groner & Durig 1977), the astrophysical interest for the complete description of the spectrum in the millimeter and submillimeter regions of DME and its isotopologues, such as 13 CH 3 OCH 3 ( 13 C-DME) and CH 3 OCH 2 D (d-DME), has brought about many laboratory studies of its rotational spectrum and of a few vibrational bands (Lovas et al 1979;Neustock et al 1990;Groner et al 1998;Coudert et al 2002;Niide & Hayashi 2003;Endres et al 2009;Kutzer et al 2016). In turn, the analysis of an extensive number of spectral lines in astronomical observations has given rise to the identification of DME in Orion-KL  (Brouillet et al 2013) and the detection of the first excited torsional states lines in a high-mass star-forming region  ).…”

New spectral characterization of dimethyl ether isotopologues CH$_3$OCH$_3$ and $^{13}$CH$_3$OCH$_3$ in the THz region

“…In addition to works prior to its detection in the ISM (Taylor & Vidale 1957;Kasai & Myers 1959;Fateley & Miller 1962;Blukis et al 1963;Durig et al 1976;Groner & Durig 1977), the astrophysical interest for the complete description of the spectrum in the millimeter and submillimeter regions of DME and its isotopologues, such as 13 CH 3 OCH 3 ( 13 C-DME) and CH 3 OCH 2 D (d-DME), has brought about many laboratory studies of its rotational spectrum and of a few vibrational bands (Lovas et al 1979;Neustock et al 1990;Groner et al 1998;Coudert et al 2002;Niide & Hayashi 2003;Endres et al 2009;Kutzer et al 2016). In turn, the analysis of an extensive number of spectral lines in astronomical observations has given rise to the identification of DME in Orion-KL (Brouillet et al 2013) and the detection of the first excited torsional states lines in a high-mass star forming region (Bisschop et al 2013).…”