Ion imaging study of reaction dynamics in the N{sup +}+ CH{sub 4} system

Journal Article · Sun Oct 21 04:00:00 EDT 2012 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4759265· OSTI ID:22099064

Pei, Linsen; Farrar, James M. ^[1]

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1. Department of Chemistry, University of Rochester, Rochester, New York 14627 (United States)

The velocity map ion imaging method is applied to the ion-molecule reactions of N{sup +} with CH{sub 4}. The velocity space images are collected at collision energies of 0.5 and 1.8 eV, providing both product kinetic energy and angular distributions for the reaction products CH{sub 4}{sup +}, CH{sub 3}{sup +}, and HCNH{sup +}. The charge transfer process is energy resonant and occurs by long-range electron transfer that results in minimal deflection of the products. The formation of the most abundant product, CH{sub 3}{sup +}, proceeds by dissociative charge transfer rather than hydride transfer, as reported in earlier publications. The formation of HCNH{sup +} by C-N bond formation appears to proceed by two different routes. The triplet state intermediates CH{sub 3}NH{sup +} and CH{sub 2}NH{sub 2}{sup +} that are formed as N{sup +}({sup 3}P) approaches CH{sub 4} may undergo sequential loss of two hydrogen atoms to form ground state HCNH{sup +} products on a spin-allowed pathway. However, the kinetic energy distributions for formation of HCNH{sup +} extend past the thermochemical limit to form HCNH{sup +}+ 2H, implying that HCNH{sup +} may also be formed in concert with molecular hydrogen, and requiring that intersystem crossing to the singlet manifold must occur in a significant ({approx}25%) fraction of reactive collisions. We also report GAUSSIAN G2 calculations of the energies and structures of important singlet and triplet [CNH{sub 4}{sup +}] complexes that serve as precursors to product formation.

• OSTI ID: 22099064
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 15 Vol. 137; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
CHARGE EXCHANGE
DISSOCIATION
ELECTRON TRANSFER
EV RANGE 01-10
GROUND STATES
HYDRIDES
HYDROGEN
ION-MOLECULE COLLISIONS
KINETIC ENERGY
METHANE
MOLECULAR STRUCTURE
REACTION KINETICS
TRIPLETS
VELOCITY