Determination of stepsize parameters for intermolecular vibrational energy transfer

Technical Report · Sun Mar 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/5444681· OSTI ID:5444681

Tardy, D C

Intermolecular energy transfer of highly excited polyatomic molecules plays an important role in many complex chemical systems: combustion, high temperature and atmospheric chemistry. By monitoring the relaxation of internal energy we have observed trends in the collisional efficiency ({beta}) for energy transfer as a function of the substrate's excitation energy and the complexities of substrate and deactivator. For a given substrate {beta} increases as the deactivator's mass increase to {approximately}30 amu and then exhibits a nearly constant value; this is due to a mass mismatch between the atoms of the colliders. In a homologous series of substrate molecules (C{sub 3}{minus}C{sub 8}) {beta} decreases as the number of atoms in the substrate increases; replacing F with H increases {beta}. All substrates, except for CF{sub 2}Cl{sub 2} and CF{sub 2}HCl below 10,000 cm{sup {minus}1}, exhibited that {beta} is independent of energy, i.e. <{Delta}E>{sub all} is linear with energy. The results are interpreted with a simple model which considers that {beta} is a function of the ocillators energy and its vibrational frequency. Limitations of current approximations used in high temperature unimolecular reactions were evaluated and better approximations were developed. The importance of energy transfer in product yields was observed for the photoactivation of perfluorocyclopropene and the photoproduction of difluoroethyne. 3 refs., 18 figs., 4 tabs.

• Research Organization: Iowa Univ., Iowa City, IA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-87ER13700
• OSTI ID: 5444681
• Report Number(s): DOE/ER/13700-T2; ON: DE92010770
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical &amp; Physicochemical Properties
400500 -- Photochemistry
664400* -- Experimentally Derived Information on Atomic &amp; Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
CHEMICAL REACTIONS
DOCUMENT TYPES
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
FLUORINATED ALICYCLIC HYDROCARBONS
HALOGENATED ALICYCLIC HYDROCARBONS
MOLECULES
MONITORING
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OSCILLATOR STRENGTHS
PHOTOCHEMICAL REACTIONS
POLYATOMIC MOLECULES
PROGRESS REPORT
RELAXATION
TEMPERATURE DEPENDENCE
VIBRATIONAL STATES