Ion–molecule reaction mechanisms: Thermal energy gas phase reactions of 12C+ and 13C+ ions with CH4, C2H4, C2H6, C3H6, C3H8, and CD3CH2CD3

1976 ◽  
Vol 65 (7) ◽  
pp. 2574-2583 ◽  
Author(s):  
Richard D. Smith ◽  
Jean H. Futrell
Keyword(s):  
Gas Phase ◽  
Thermal Energy ◽  
Reaction Mechanisms ◽  
Gas Phase Reactions ◽  
Molecule Reaction

scholarly journals The formation of urea in space

2018 ◽  
Vol 610 ◽  
pp. A26 ◽  
Author(s):  
Flavio Siro Brigiano ◽  
Yannick Jeanvoine ◽  
Antonio Largo ◽  
Riccardo Spezia
Keyword(s):  
Activation Energy ◽  
Interstellar Medium ◽  
Gas Phase ◽  
Organic Molecules ◽  
Peptide Bond ◽  
Biological Molecules ◽  
Gas Phase Reactions ◽  
Molecule Reaction ◽  
Quantum Chemistry Calculations ◽  
Highly Correlated

Context. Many organic molecules have been observed in the interstellar medium thanks to advances in radioastronomy, and very recently the presence of urea was also suggested. While those molecules were observed, it is not clear what the mechanisms responsible to their formation are. In fact, if gas-phase reactions are responsible, they should occur through barrierless mechanisms (or with very low barriers). In the past, mechanisms for the formation of different organic molecules were studied, providing only in a few cases energetic conditions favorable to a synthesis at very low temperature. A particularly intriguing class of such molecules are those containing one N–C–O peptide bond, which could be a building block for the formation of biological molecules. Urea is a particular case because two nitrogen atoms are linked to the C–O moiety. Thus, motivated also by the recent tentative observation of urea, we have considered the synthetic pathways responsible to its formation. Aims. We have studied the possibility of forming urea in the gas phase via different kinds of bi-molecular reactions: ion-molecule, neutral, and radical. In particular we have focused on the activation energy of these reactions in order to find possible reactants that could be responsible for to barrierless (or very low energy) pathways. Methods. We have used very accurate, highly correlated quantum chemistry calculations to locate and characterize the reaction pathways in terms of minima and transition states connecting reactants to products. Results. Most of the reactions considered have an activation energy that is too high; but the ion-molecule reaction between NH2OHNH2OH2+ and formamide is not too high. These reactants could be responsible not only for the formation of urea but also of isocyanic acid, which is an organic molecule also observed in the interstellar medium.

GAS-PHASE REACTIONS OF V+ AND VO+ WITH METHANOL

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2693-2698 ◽  
Author(s):  
YALI CAO ◽  
XIANG ZHAO ◽  
ZICHAO TANG ◽  
BIN XIN ◽  
SHAOXIANG XIONG
Keyword(s):  
Reaction Time ◽  
Dft Calculations ◽  
Ab Initio ◽  
Gas Phase ◽  
Reaction Mechanisms ◽  
Ab Initio Calculation ◽  
Gas Phase Reactions ◽  
Geometrical Structures ◽  
Reaction Processes ◽  
Ft Icr

The reactions of V + and VO + with methanol have been investigated experimentally by FT-ICR mass spectrometer and theoretically by ab initio calculation. Both V + and VO + exhibit impressive reactivity with methanol. The products distribution of different reaction time indicate that in whole reaction processes methanol is adsorbed one by one, and no more than four methanol molecules can be solved in the first shell of central ion V +. The reaction mechanisms have been proposed, and the possible geometrical structures of products are also analyzed by DFT calculations.

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