Collisional quenching of A /sup 2/. sigma. /sup +/ OH at elevated temperatures

Journal Article · Mon Aug 15 04:00:00 EDT 1983 · J. Chem. Phys.; (United States)

OSTI ID:5913456

Fairchild, P W; Smith, G P; Crosley, D R

Thermally averaged cross sections sigma/sub Q/ for collisional quenching of the A /sup 2/..sigma../sup +/ state of the OH molecule have been measured near 1100 K. The OH was produced and detected in a laser pyrolysis/laser fluorescence experiment, in which a mixture of SF/sub 6/, H/sub 2/O/sub 2/, and the collision partner M was heated by a pulsed CO/sub 2/ laser. Thermal decomposition of the peroxide produces OH which is then excited by a tunable laser; the real-time decay of the fluorescence signal at different pressures of M furnishes sigma/sub Q/. These sigma/sub Q/ at elevated temperatures are generally less than the room temperature values. This result, the size of sigma/sub Q/, and its variation with M suggest the importance of attractive forces in the collisional quenching. The experimental results have been compared with a theoretical calculation of sigma/sub Q/ based on multipole attractive forces with a repulsive centrifugal barrier. Good correlation is obtained for eight of the 11 quenchers studied; the experimental values of sigma/sub Q/ for N/sub 2/ and SF/sub 6/ are conspicuously low.

• Research Organization: Molecular Physics Laboratory, SRI International, Menlo Park, California 94025
• OSTI ID: 5913456
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 79:4; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
CHEMICAL REACTIONS
COLLISIONS
CROSS SECTIONS
DE-EXCITATION
DECOMPOSITION
DEUTERIUM
ELEMENTS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROGEN PEROXIDE
HYDROXYL RADICALS
ISOTOPES
LIGHT NUCLEI
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NITROGEN
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
PEROXIDES
PYROLYSIS
RADIATIONLESS DECAY
RADICALS
STABLE ISOTOPES
SULFUR COMPOUNDS
SULFUR FLUORIDES
THERMOCHEMICAL PROCESSES
VERY HIGH TEMPERATURE