Effect of vibrational excitation on the dynamics of ion-molecule reactions

Technical Report · Sun Nov 01 04:00:00 EST 1981

DOI:https://doi.org/10.2172/5788667· OSTI ID:5788667

Anderson, S L

A new experimental technique for the study of vibrational effects on ion-molecule reaction cross sections is described. Vibrational and collision energy dependent cross sections are presented for proton and H atom transfer, charge transfer and collision induced dissociation reactions in various isotopic H/sub 2//sup +/ + H/sub 2/ systems. Charge and proton transfer cross sections are presented for the reactions of H/sub 2//sup +/ and D/sub 2//sup +/ with Ar, N/sub 2/, CO, and O/sub 2/. All the reactions are shown to be highly influenced by avoided crossings between the ground and first excited potential energy surfaces. Because of the nature of the crossings, vibrational motion of the systems can cause both adiabatic and non-adiabatic behavior of the system. This makes the vibrational dependences of the various cross sections a very sensitive probe of the dynamics of the collisions particularly, their behavior in the region of the crossings. Evidence is seen for charge transfer between reagents as they approach each other, transition to and in some cases reactions on excited potential energy surfaces, competition between different channels, and strong coupling of proton and charge transfer channels which occurs only for two of the systems studied (H/sub 2//sup +/ + Ar, N/sub 2/). Oscillatory structure is observed in the collision energy dependence of the endoergic H/sub 2//sup +/ (v = 0) + Ar charge transfer reaction for the first time, and a simple model which is commonly used for atom-atom charge transfer is used to fit the peaks. Finally a simple model is used to assess the importance of energy resonance and Franck-Condon effects on molecular charge transfer.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5788667
• Report Number(s): LBL-13309; ON: DE82004951
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CATIONS
CHALCOGENIDES
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DATA
DEUTERIUM IONS
DISSOCIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
EXPERIMENTAL DATA
FLUIDS
GASES
HYDROGEN
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
HYDROGEN IONS 2 PLUS
INFORMATION
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONS
KINETICS
MOLECULAR IONS
MOLECULE COLLISIONS
NITROGEN
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN
OXYGEN COMPOUNDS
POTENTIALS
RARE GASES
REACTION KINETICS
RESONANCE
VIBRATIONAL STATES