Related Experiment Video
Updated: Jul 18, 2026
08:14
Ammonia Synthesis at Low Pressure
Published on: August 23, 2017
Dissociative recombination of ammonia clusters studied by storage ring experiments
J Ojekull1, P U Andersson, M B Någård
1Department of Chemistry, Atmospheric Science, Göteborg University, SE-412 96 Göteborg, Sweden.
The Journal of Chemical Physics
|November 30, 2006
Summary
Dissociative recombination of ammonia cluster ions with electrons was studied. Fragmentation patterns showed no isotope effect, with dominant channels yielding ammonia molecules and atoms.
Area of Science:
- Chemical Physics
- Atomic and Molecular Physics
- Plasma Physics
Background:
- Ammonia cluster ions are relevant in various chemical and astrophysical environments.
- Understanding dissociative recombination is crucial for modeling plasma chemistry.
Purpose of the Study:
- To investigate the dissociative recombination of ammonia cluster ions (H+(NH3)2, H+(NH3)3, D+(ND3)2, D+(ND3)3) with electrons.
- To determine absolute cross sections and calculate thermal rate coefficients.
- To analyze fragmentation patterns and isotope effects.
Main Methods:
- Experiments were conducted at the CRYRING heavy-ion storage ring.
- Absolute cross sections were measured for collision energies from 0.001 to 27 eV.
- Thermal rate coefficients were calculated for temperatures between 10 and 1000 K.
Main Results:
- Absolute cross sections for ammonia cluster ions were reported.
- No significant isotope effect was observed in the fragmentation of H+(NH3)2 and D+(ND3)2.
- Dissociative recombination of X+(NX3)2 predominantly yielded 2NX3+X, while D+(ND3)3 favored three N-containing fragments.
Conclusions:
- Dissociative recombination of ammonia cluster ions proceeds through specific fragmentation channels.
- The findings contribute to a better understanding of ion-molecule reactions in plasmas and interstellar environments.
Related Concept Videos
01:15Mass Spectrometry of Amines
In mass spectroscopy, amines undergo fragmentation to give parent ions with odd molecule weights. This observed mass spectrum follows the nitrogen rule; a molecule with an odd number of nitrogen atoms produces a molecular ion with an odd molecular weight. Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit strong molecular ion peaks, but acyclic aliphatic amines show...
00:55Mass Spectrometry: Amine Fragmentation
Amines can be identified using mass spectroscopy based on their characteristic fragmentation patterns. The molecular ions of amines undergo fragmentation via ⍺-cleavage. The ⍺-cleavage of the carbon-carbon bonds in amines generates an alkyl radical and resonance-stabilized nitrogen-containing cation.
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing a single or...
01:30Preparation of Amines: Alkylation of Ammonia and Amines
Alkylation is one of the methods used to prepare amines. Direct alkylation of ammonia or a primary amine with an alkyl halide gives polyalkylated amines along with a quaternary ammonium salt through successive SN2 reactions. This process of making the quaternary salt through the direct alkylation method is called exhaustive alkylation.
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
01:19Structure of Amines
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...
01:07Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...