Rates of photoisomerization of trans-stilbene in isolated and solvated molecules: experiments on the deuterium isotope effect and RRKM behavior

Journal Article · Thu Dec 05 00:00:00 EST 1985 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100271a018· OSTI ID:6035648

Felker, P M; Zewail, A H

In this paper the dynamics of the photoisomerization of trans-stilbene and related molecules are considered. New measurements of the deuterium isotope effect on reaction rates are presented, and details of RRKM behavior in isolated and solvated trans-stilbene are discussed. From measurements of fluorescence decay rates as a function of the excess vibrational energy in jet-cooled trans-stilbene-d/sup 12/, an energy threshold to the rates is found at ca. 1200-cm/sup -1/ excess energy in the first excited singlet state. The threshold behavior is similar to that which occurs in the photoisomerization of trans-stilbene-h/sup 12/. The overall magnitudes of the perdeuterio rates are smaller, however, than the perprotio ones. As with trans-stilbene-h/sup 12/ the measured rates are found to be slower than those calculated by standard RRKM theory. Nevertheless, the observed slowing of the rates upon deuteration is predicted by the theory. The results and their interpretation are discussed in light of the results of other jet studies of trans-stilbene derivatives and of studies of the photoisomerization reaction in solution. The role of intramolecular vibrational energy redistribution and the nonadiabatic influences on the reaction are also discussed. 53 references, 4 figures, 3 tables.

• Research Organization: California Institute of Technology (CalTech), Pasadena, CA (United States)
• OSTI ID: 6035648
• Journal Information: J. Phys. Chem.; (United States), Vol. 89:25
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
STILBENE
ISOMERIZATION
PHOTOCHEMICAL REACTIONS
CHEMICAL REACTION KINETICS
DEUTERIUM COMPOUNDS
EXPERIMENTAL DATA
FLUORESCENCE
ISOTOPE EFFECTS
PHOTOCHEMISTRY
PREDICTION EQUATIONS
RADIATIVE DECAY
AROMATICS
CHEMICAL REACTIONS
CHEMISTRY
DATA
EQUATIONS
HYDROCARBONS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
LUMINESCENCE
NUMERICAL DATA
ORGANIC COMPOUNDS
REACTION KINETICS
400500* - Photochemistry