Collisional relaxation of vibrationally excited O/sub 2//sup +/ ions

Journal Article · Tue Nov 01 04:00:00 EST 1983 · J. Chem. Phys.; (United States)

OSTI ID:5636823

Boehringer, H; Durup-Ferguson, M; Fahey, D W; Fehsenfeld, F C; Ferguson, E E

Vibrationally excited O/sub 2//sup +/ ions were produced and injected into a helium flow tube and found to survive more than 10/sup 5/ collisions with He atoms without significant relaxation. The first, second, and higher vibrational states of O/sub 2//sup +/ were detected by their enhanced reactions with Xe, SO/sub 2/, and H/sub 2/O. Using these reactions as probes for vibrational excitation, the relaxation of O/sub 2//sup +/ (v = 1) and O/sub 2//sup +/ (v = 2) ions was studied for collisions with Ne, Ar, Kr, H/sub 2/, D/sub 2/, N/sub 2/, CO, CO/sub 2/, H/sub 2/O, CH/sub 4/, SO/sub 2/, SF/sub 6/, and O/sub 2/. The resulting quenching rate constants were found to vary from 1(-9) to <2(-15) cm/sup 3/ s/sup -1/. The quenching rate constant of O/sub 2//sup +/ (v = 2) was approximately twice that of O/sub 2//sup +/ (v = 1) in each case. The rate constants were found to correlate with the bond energy of the ion--molecule collision complex. For CO/sub 2/, Kr, and O/sub 2/, the energy dependence of the quenching rate constant was investigated in the range 0.04--0.3 eV. The results indicate that the relaxation process proceeds through a long-lived complex where the vibrational excitation is transferred into the weak complex bond resulting in dissociation, analogous to vibrational predissociation in van der Waals complexes. In the special case of O/sub 2//sup +/ (v)--O/sub 2/ collisions, the relaxation is clearly dominated by the resonant charge transfer process and the rate constants for v = 1 and v = 2 are found to be equal.

• Research Organization: Aeronomy Laboratory, NOAA Environmental Research Laboratories, Boulder, Colorado 80303
• OSTI ID: 5636823
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 79:9; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular &amp; Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKANES
ARGON
ATOM COLLISIONS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COLLISIONS
DEUTERIUM
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
ION COLLISIONS
ION-ATOM COLLISIONS
ION-MOLECULE COLLISIONS
IONS
ISOTOPES
KRYPTON
LIGHT NUCLEI
METHANE
MOLECULAR IONS
MOLECULE COLLISIONS
NEON
NITROGEN
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
OXYGEN IONS
RARE GASES
RELAXATION
STABLE ISOTOPES
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR FLUORIDES
SULFUR OXIDES
VAPORS
VIBRATIONAL STATES
WATER VAPOR