Related Experiment Video
Updated: Sep 26, 2026
Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
Published on: December 6, 2021
An Ab initio study on the mechanism of the atmospheric reaction NH2 + O3-->H2NO + O2
Julio Peiró-García1, Ignacio Nebot-Gil, Manuela Merchán
1Instituto de Ciencia Molecular Departamento de Química Física Facultad de Química, Universidad de Valencia, c/Dr. Moliner, 50, 46100, Burjasot, Spain.
Abstract:
The atmospheric reaction NH2 + O3-->H2NO + O2 has been investigated theoretically by using MP2, QCISD, QCISD(T), CCSD(T), CASSCF, and CASPT2 methods with various basis sets. At the MP2 level of theory, the hypersurface of the potential energy (HPES) shows a two step reaction mechanism. Therefore, the mechanism proceeds along two transition states (TS1 and TS2), separated by an intermediate designated as Int. However, when the single-reference higher correlated QCISD and the multiconfigurational CASSCF methodologies have been employed, the minimum structure Int and TS2 are not found on the HPES, which thus confirms a direct reaction mechanism. Single-reference high correlated and multiconfigurational methods consistently predict the barrier height of the reaction to be within the range of 3.9 to 6.6 kcal mol-1, which is somewhat higher than the experimental value. The calculated reaction enthalpy is -67.7 kcal mol-1.
Related Concept Videos
02:50Catalysis
01:27Catalysis
02:31Multi-Step Reactions
03:12Chemical Stoichiometry and Gases: Using Ideal Gas Law to Determine Moles
02:34Nucleophilic Substitution Reactions
In 1896, the German chemist Paul Walden discovered that he could interconvert pure enantiomeric (+) and (-) malic acids through a series of reactions. This conversion suggested the involvement of optical inversion during the substitution reaction. Further, in 1930, Sir Christopher Ingold described for the first time two different forms of nucleophilic substitution reactions, which are known as SN1 (nucleophilic substitution unimolecular) and SN2 (nucleophilic substitution...
03:08Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...