Torsional photoisomerization of substituted ethylenes: Application to stilbene
The trans to cis isomerization rate of stilbene is determined using a diffusional model for internal rotation. It is found that the rate is sensitive to the structural model for stilbene adopted and factors of 2 can be introduced by assuming the phenyl substituents are spherical. The preferred model treats the phenyl substituents as collections of six spheres rigidly bound together and having a specific pitch angle with respect to the plane of the ethylene double bond. The use of a model potential function, chosen to agree qualitatively with experimental findings, allows the calculation of the isomerization rate as a function of the height of the barrier to rotation Q. The experimental value for the rate can be fit with this model using a barrier height ranging from 2--3 kcal/mole, in accord with previous estimates.
- Research Organization:
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331
- OSTI ID:
- 6399699
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 74:8; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AROMATICS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
HYDROCARBONS
ISOMERIZATION
KINETICS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
REACTION KINETICS
STILBENE
TORSION