منابع مشابه
Interstellar Triply Deuterated Ammonia
Research on interstellar ND3 is reviewed and updated from the discovery papers. Results from observations of a dozen sources at centimeter and submillimeter wavelengths are presented. The two data sets are consistent, but do not constrain the excitation conditions in the ND3emitting gas. The column density ratios of NH3/NH2D, NH2D/ND2H and ND3/ND2H, observed in similar sized beams, are ≈10, and...
متن کاملDeuterated Ammonia in Galactic Protostellar Cores
We report on a survey of NH2D towards protostellar cores in low–mass star formation and quiescent regions in the Galaxy. Twenty–three out of thirty-two observed sources have significant (∼5σ) NH2D emission. Ion–molecule chemistry, which preferentially enhances deuterium in molecules above its cosmological value of 1.6× 10 sufficiently explains these abundances. NH2D/NH3 ratios towards Class 0 s...
متن کاملAnisotropic Spin -Lattice Relaxation of Deuterated Hexamethylbenzene
The anisotropic spin-lattice relaxation of deuterated hexamethy lbenzene (HMB-d,,) was measured at -36 and 70°C. The anisotropy is due to the anisotropic sixfold reorientation of the molecule about its hexad axis, and a model is presented to explain quantitatively the anisotropy, considering only single-particle relaxation. The temperature dependence of T, was measured, and the activation energ...
متن کاملRotation-tunneling spectrum of the deuterated ammonia dimer
The millimeter and submillimeter-wave molecular-beam spectrum of the perdeuterated ammonia dimer (ND3)2 has been measured between approximately 50 and 400 GHz using an electric-resonance optothermal spectrometer ~EROS!. As in the case of the (NH3)2 , the spectrum is complicated by the threefold internal rotation of the ND3 subunits, the interchange tunneling of the two subunits, and the inversi...
متن کاملSpin Relaxation in Nematogensand their Deuterated Derivatives
A brief review of spin relaxation (1) in nematogens is given. The usual problems in this area arise from the lack of a good theoretical model and a spin system in which meaningful measurements and direct comparison with the model can be made. The proton and deuteron spin-lattice relaxation in nematics have been extensively studied both theoretically (2,3) and experimentally (4-8). It is general...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2015
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361/201526468