Rotational dependence of the proton-transfer reaction HBr{sup +}+ CO{sub 2}{yields} HOCO{sup +}+ Br. II. Comparison of HBr{sup +} ({sup 2}{Pi}{sub 3/2}) and HBr{sup +} ({sup 2}{Pi}{sub 1/2})

Journal Article · Tue Dec 21 04:00:00 EST 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3515300· OSTI ID:21559962

Paetow, Lisa; Unger, Franziska; Beutel, Bernd; Weitzel, Karl-Michael ^[1]

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1. Philipps-Universitaet Marburg, Fachbereich Chemie, Hans-Meerwein-Strasse, 35032 Marburg (Germany)

The effects of reactant ion rotational excitation on the exothermic proton-transfer reactions of HBr{sup +}({sup 2}{Pi}{sub 1/2}) and DBr{sup +}({sup 2}{Pi}{sub 1/2}), respectively, with CO{sub 2} were studied in a guided ion beam apparatus. Cross sections are presented for collision energies in the center of mass system E{sub c.m.} in the range of 0.23 to 1.90 eV. The HBr{sup +}/DBr{sup +} ions were prepared in a state-selective manner by resonance enhanced multiphoton ionization. The mean rotational energy was varied from 3.4 to 46.8 meV for HBr{sup +}({sup 2}{Pi}{sub 1/2}) and from 1.8 to 40.9 meV for DBr{sup +}({sup 2}{Pi}{sub 1/2}). Both reactions studied are inhibited by collision energy, as expected for exothermic reactions. For all collision energies considered, the cross section decreases with increasing rotational energy of the ion, but the degree of the rotational dependence differs depending on the collision energy. For E{sub c.m.}= 0.31 eV, the cross sections of the deuteron transfer are significantly larger than those of the proton transfer. For higher E{sub c.m.} they differ very little. The current results for the exothermic proton transfer are systematically compared to previously published data for the endothermic proton transfer starting from HBr{sup +}({sup 2}{Pi}{sub 3/2}) [L. Paetow et al., J. Chem. Phys. 132, 174305 (2010)]. Additional new data regarding the latter reaction are presented to further confirm the conclusions. The dependences on rotational excitation found cannot be explained by the corresponding change in the total energy of the system. For both the endothermic and the exothermic reaction, the cross section is maximized for the smallest rotational energy, at least well above the threshold.

• OSTI ID: 21559962
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 23 Vol. 133; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BARYONS
BEAMS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CATIONS
CENTER-OF-MASS SYSTEM
CHALCOGENIDES
CHARGED PARTICLES
COLLISIONS
COMPARATIVE EVALUATIONS
CROSS SECTIONS
DEUTERONS
DIRECT REACTIONS
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVALUATION
EXCITATION
EXCITED STATES
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
ION BEAMS
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONIZATION
IONS
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
MOLECULES
MULTI-PHOTON PROCESSES
NUCLEAR REACTIONS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
PHOTON COLLISIONS
PHOTON-MOLECULE COLLISIONS
PROTONS
RESONANCE
ROTATIONAL STATES
TRANSFER REACTIONS