Green Bank Telescope Detection of New Interstellar Aldehydes: Propenal and Propanal

The new interstellar molecules propenal (CH2CHCHO) and propanal (CH3CH2CHO) have been detected largely in absorption toward the star-forming region Sagittarius B2(N) by means of rotational transitions observed with the 100 m Green Bank Telescope (GBT) operating in the range from 18 GHz (λ ~ 1.7 cm) to 26 GHz (λ ~ 1.2 cm). The GBT was also used to observe the previously reported interstellar aldehyde propynal (HC2CHO) in Sagittarius B2(N), which is a known source of large molecules presumably formed on interstellar grains. The presence of these three interstellar aldehydes toward Sagittarius B2(N) strongly suggests that simple hydrogen addition on interstellar grains accounts for successively larger molecular species: from propynal to propenal and from propenal to propanal. Energy sources within Sagittarius B2(N) likely permit the hydrogen addition reactions on grain surfaces to proceed. This work demonstrates that successive hydrogen addition is probably an important chemistry route in the formation of a number of complex interstellar molecules. We also searched for but did not detect the three-carbon sugar glyceraldehyde (CH2OHCHOHCHO)

Rotational spectrum and tentative detection of DCOOCH3–Methyl formate in Orion

New centimeter-wave (7–80 GHz) and submillimeter-wave (580–661 GHz) 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. 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 94.2 kHz. The dipole moment and the nuclear quadrupole coupling constants of the deuterated specie have also been obtained. This new study has permitted a tentative detection of DCOOCH3 in Orion with the IRAM 30 m 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 7.8 × 1014 cm−2 and theDCOOCH3/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

Icosahedral Carbaboranes with Peripheral Hydrogen–Chalcogenide Groups : Structures from Gas Electron Diffraction and Chemical Shielding in Solution

Carbaboranes 1,2-(EH)2-closo-1,2-C2B10H10 (E=S, Se) were prepared, in the case of E=Se for the first time. Their semi-experimental equilibrium molecular structures were established by the concerted use of quantum-chemical calculations and gas electron diffraction. A method was developed and implemented to quantify the contribution of experimental data to each refined structural parameter. The accuracy of the experimental structures and those calculated at the MP2 level of theory were gauged by comparison of experimental 11B NMR chemical shifts with quantum-chemically computed values; the inclusion of electron correlation (GIAO-MP2) provided superior results. For the purpose of geometrical prediction, the remaining group 16 elements were considered, and the icosahedral structures for E=O and Te were also computed; for E=O the same theoretical approach was used as for E=S, and for E=Te a description similar to that for E=Se was employed

"To the Lighthouse" - en hermeneutisk provokasjon : en analyse av karakterene i Virginia Woolfs "To the Lighthouse" med utgangspunkt i Gérard Genettes termer fokalisering og distanse

Denne analysen av karakterene i To the Lighthouse tar utgangspunkt i Gérard Genettes termer fokalisering og perspektiv. Det vil bli vist hvordan disse to narrative begrepene har stor betydning for utformingen av karakterene. Analysen er delt opp i to deler. Den første delen, perspektiv, består av tre kapitler, hvor titlene henspeiler til Genettes tredeling av fokalisering. Det første kapitlet, internfokalisering, tar for seg hvordan karakterene fremstilles gjennom de forskjellige personenes perspektiv. Sentralt i dette står tolkningen av hvordan karakterene tolker andres tanker, følelser og adferd. Leseren får bare subjektive opplysninger om de forskjellige karakterene, og vil derfor aldri få et objektivt fortellerperspektiv. Dette medfører at leseren må vurdere alt som har blitt fortalt om en karakter, og også dem opplysningene er fokalisert igjennom. Internfokalisering fører til at karakterene aldri står frem som faste enheter. De vil aldri helt kunne gripes. Internfokalisering viser også hvordan bevisstheten arbeider. I dette kapittelet vil også fortellerens rolle diskuteres. Både kapitel II, nullfokalisering, og kapitel III, eksternfokalisering har som funksjon i denne romanen, det Genette kaller alterations. Han definerer det som brudd med den dominerende tendensen, som i To the Lighthouse er internfokalisering. Disse bruddene har stor betydning for hvordan leseren vil tolke karakterene. Del II, er delt opp i to kapitler: hvorfor alltid distanse og distanse som et virkemiddel for å beskrive sinnets kompleksitet. Denne delen tar for seg distansen to sider. Fortelleren er distansert fra sine karakterer, og han benytter denne avstanden for å vise sine holdninger. Samtidig er distanse nødvendig for å kunne beskrive psykens kompleksitet

Rotational spectrum of ethyl cyanoacetylene (C

Context. New radiotelescopes, such as the very sensitive ALMA, will enable the detection of interstellar molecules in much lower concentrations than previously possible. A successful identification of an interstellar molecule requires that laboratory microwave and millimeter-wave spectra are investigated. Several cyanopolyynes and alkynylcarbonitriles have already been detected in the interstellar medium (ISM). Cyanoacetylene (HC≡C–C≡N) is abundant in the ISM and its methyl derivative, 2-butynenitrile (CH3C≡C–C≡N), is also present. The next derivative, ethyl cyanoacetylene, (2-pentynenitrile C2H5C≡C–C≡N) may also be present in interstellar space. Aims. We report the rotational spectrum of the ethyl cyanoacetylene (C2H5C≡C–C≡N). This is hoped to facilitate identifying gaseous ethyl cyanoacetylene in the ISM. Methods. We studied the rotational spectrum of C2H5C≡C–C≡N between 13 and 116 GHz with the microwave spectrometer of the University of Oslo. The spectroscopic study was augmented by high-level quantum-chemical calculations at B3LYP/cc-pVTZ and CCSD/cc-pVTZ levels of theory. Results. We present for the first time the rotational spectrum of the ethyl cyanoacetylene (C2H5C≡C–C≡N). We assigned 342 transitions of the vibrational ground state, accurate values were obtained for rotational and centrifugal distortion constants, and the dipole moment was determined as well