Radiative lifetime and quenching rate constants of PF (b[sup 1][Sigma][sup +]) and tests for an electronic to vibrational energy transfer quenching mechanism
- Kansas State Univ., Manhattan, KS (United States)
A dc discharge in a dilute flow of PF[sub 3] in He was used as a source of PF(b[sup 1][Sigma][sup +]) molecules in a flow reactor to measure the radiative lifetime and quenching rate constants for 38 reagent molecules at 300 K. The concentration of PF(b[sup 1][Sigma][sup +]) in the reactor was about 2 x 10[sup 8] molecule cm[sup [minus]3]. The decay rate of the PF(b[sup 1][Sigma][sup +]) concentration was monitored from the intensity of the PF(b-X) transition, and the radiative lifetime was measured to be 9.7 [+-] 1.2 ms. The quenching rate constants are small, except for O[sub 2] and Cl[sub 2], and in the range 10[sup [minus]12]-10[sup [minus]14] cm[sup 3] molecule[sup [minus]1] s[sup [minus]1]. The dependence of the other rate constants on properties of the reagent is consistent with an electronic-to-vibrational (E-V) quenching mechanism, and this was confirmed by studying several isotopic pairs of molecules, such as H[sub 2]/D[sub 2], H[sub 2]O/D[sub 2]O, and CH[sub 3]CN/CD[sub 3]CN. The quenching rate constants are compared to predictions of a model for E-V energy transfer. The reaction with O[sub 2] proceeds by electronic energy transfer to give O[sub 2](b[sup 1][Sigma][sup +]). 39 refs., 9 figs., 3 tabs.
- OSTI ID:
- 6768054
- Journal Information:
- Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:39; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
250800 -- Energy Storage-- Chemical
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
661300 -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL REACTORS
ELECTRIC DISCHARGES
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
ENERGY STORAGE
ENERGY TRANSFER
EXCITED STATES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
KINETICS
MATHEMATICAL MODELS
NONMETALS
OXYGEN
PHOSPHORUS COMPOUNDS
PHOSPHORUS FLUORIDES
PHOTOCHEMICAL ENERGY STORAGE
QUENCHING
REACTION KINETICS
STORAGE
VIBRATIONAL STATES