Theory of polarized fluorescence of polyatomic radicals upon photodissociation of complex molecules in the gas phase

1998 ◽  
Vol 65 (6) ◽  
pp. 952-959
Author(s):  
A. P. Blokhin ◽  
M. F. Gelin
Keyword(s):  
Gas Phase ◽  
Polarized Fluorescence ◽  
Complex Molecules

Polarized fluorescence of radicals in photodissociation of disulfides in the gas phase

1999 ◽  
Vol 66 (1) ◽  
pp. 55-61 ◽  
Author(s):  
A. P. Blokhin ◽  
M. F. Gelin ◽  
I. I. Kalosha ◽  
S. A. Polubisok ◽  
V. A. Tolkachev
Keyword(s):  
Gas Phase ◽  
Polarized Fluorescence

Non-thermal ion desorption from an acetonitrile (CH3CN) astrophysical ice analogue studied by electron stimulated ion desorption

2015 ◽  
Vol 17 (41) ◽  
pp. 27473-27480 ◽  
Author(s):  
F. de A. Ribeiro ◽  
G. C. Almeida ◽  
Y. Garcia-Basabe ◽  
W. Wolff ◽  
H. M. Boechat-Roberty ◽  
...  
Keyword(s):  
Gas Phase ◽  
Electron Impact ◽  
Thermal Desorption ◽  
Complex Molecules ◽  
Ion Desorption

Non-thermal desorption by electron impact constitutes an important route by which neutral and ionic fragments from simple nitrile-bearing ices may be delivered back to the gas-phase of astrophysical environments, contributing to the production of more complex molecules.

scholarly journals Laboratory constraints on ice formation, restructuring and desorption

2015 ◽  
Vol 11 (A29A) ◽  
pp. 309-312
Author(s):  
Karin I. Öberg
Keyword(s):  
Gas Phase ◽  
Chemical Reactions ◽  
Organic Molecules ◽  
Protoplanetary Disks ◽  
Ice Formation ◽  
Circumstellar Dust ◽  
Dust Grains ◽  
Complex Molecules ◽  
Detailed Understanding ◽  
Complex Organic

AbstractIces form on the surfaces of interstellar and circumstellar dust grains though freeze-out of molecules and atoms from the gas-phase followed by chemical reactions. The composition, chemistry, structure and desorption properties of these ices regulate two important aspects of planet formation: the locations of major condensation fronts in protoplanetary disks (i.e. snow lines) and the formation efficiencies of complex organic molecules in astrophysical environments. The latter regulates the availability of prebiotic material on nascent planets. With ALMA it is possible to directly observe both (CO) snowlines and complex organics in protoplanetary disks. The interpretation of these observations requires a detailed understanding of the fundamental ice processes that regulate the build-up, evolution and desorption of icy grain mantles. This proceeding reviews how experiments on thermal CO and N2 ice desorption, UV photodesorption of CO ice, and CO diffusion in H2O ice have been used to guide and interpret astrochemical observations of snowlines and complex molecules.

scholarly journals A confusion-limited spectral-line survey of Sgr B2(N) at 1, 2, and 3mm: Establishing the organic inventory in molecular clouds

2008 ◽  
Vol 4 (S251) ◽  
pp. 27-28 ◽  
Author(s):  
DeWayne T. Halfen ◽  
Lucy M. Ziurys
Keyword(s):  
Spectral Line ◽  
Gas Phase ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Current Data ◽  
Complex Molecules ◽  
Preliminary Results ◽  
Prebiotic Molecules ◽  
Line Survey

AbstractWe present preliminary results of an spectral-line survey at 1, 2, and 3 mm of the galactic center cloud Sgr B2(N). With the current data, several simple prebiotic molecules have been conclusively identified, while several more complex molecules have not. When complete, this survey will provide an accurate database of the gas-phase organic inventory in Sgr B2(N).

scholarly journals Chemical complexity in the Horsehead photodissociation region

2014 ◽  
Vol 168 ◽  
pp. 103-127 ◽  
Author(s):  
Viviana V. Guzmán ◽  
Jérôme Pety ◽  
Pierre Gratier ◽  
Javier R. Goicoechea ◽  
Maryvonne Gerin ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Gas Phase ◽  
Thermal Desorption ◽  
Organic Molecules ◽  
Dense Core ◽  
High Spectral Resolution ◽  
Complex Molecules ◽  
Chemical Complexity ◽  
Clean Environment ◽  
Complex Organic

The interstellar medium is known to be chemically complex. Organic molecules with up to 11 atoms have been detected in the interstellar medium, and are believed to be formed on the ices around dust grains. The ices can be released into the gas-phase either through thermal desorption, when a newly formed star heats the medium around it and completely evaporates the ices; or through non-thermal desorption mechanisms, such as photodesorption, when a single far-UV photon releases only a few molecules from the ices. The first mechanism dominates in hot cores, hot corinos and strongly UV-illuminated PDRs, while the second dominates in colder regions, such as low UV-field PDRs. This is the case of the Horsehead were dust temperatures are ≃20–30 K, and therefore offers a clean environment to investigate the role of photodesorption. We have carried out an unbiased spectral line survey at 3, 2 and 1mm with the IRAM-30m telescope in the Horsehead nebula, with an unprecedented combination of bandwidth, high spectral resolution and sensitivity. Two positions were observed: the warm PDR and a cold condensation shielded from the UV field (dense core), located just behind the PDR edge. We summarize our recently published results from this survey and present the first detection of the complex organic molecules HCOOH, CH2CO, CH3CHO and CH3CCH in a PDR. These species together with CH3CN present enhanced abundances in the PDR compared to the dense core. This suggests that photodesorption is an efficient mechanism to release complex molecules into the gas-phase in far-UV illuminated regions.

scholarly journals Formation of alcohols on ice surfaces

2008 ◽  
Vol 4 (S251) ◽  
pp. 377-382
Author(s):  
H. M. Cuppen ◽  
G. W. Fuchs ◽  
S. Ioppolo ◽  
S. E. Bisschop ◽  
K. I. Öberg ◽  
...  
Keyword(s):  
Gas Phase ◽  
Organic Molecules ◽  
Co Hydrogenation ◽  
Formation Rate ◽  
Physical Processes ◽  
Complex Molecules ◽  
Physical Conditions ◽  
Ethanol Formation ◽  
Hydrogenation Reactions ◽  
Reaction Routes

AbstractAs the number of detections of complex molecules keeps increasing, answering the question about their formation becomes more pressing. Many of the saturated organic molecules are found to have a very low gas phase formation rate and are therefore thought to be formed on the icy surfaces of dust grains. In the Sackler Laboratory for Astrophysics we started a systematic study of the surface reaction routes that have been suggested over the years. Here we present the experimental results on the formation of methanol and ethanol by hydrogenation reactions of carbon monoxide and acetaldehyde ice. Computer simulations of the surface processes under similar conditions using the continuous-time random-walk Monte Carlo technique reveal some of the underlying physical processes. A better understanding of the physical conditions in which these molecules are formed can help in the interpretation of the observational results. The CO hydrogenation results will appear in detail in Fuchs et al. (2008). For more details on ethanol formation we refer to Bisschop et al. (2007).

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