High pressure study of viscosity and temperature effects on tetracyanobenzene EDA complexes

Journal Article · Tue Dec 01 00:00:00 EST 1981 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.441989· OSTI ID:6243326

Thomas, M M; Drickamer, H G

High pressure fluorescence studies from 0--10 kbar have been performed on electron donor--acceptor (EDA) complexes of s-tetracyanobenzene (TCNB) with a series of aromatic hydrocarbons. Four solvents were used: 2,2,4,4,6,8,8-heptamethylnonane (HMN), methylcyclohexane (MCH), 2,6,10,14-tetramethylpentadecane (TMPD), and a mixture of MCH and HMN. A viscosity range from 0.006 to 10 000 P was covered at two temperatures: 0 and 25 /sup 0/C. As pressure (viscosity) increased the fluorescence spectrum shifted from one dominated by emission from the equilibrium (EQ) excited singlet state to one dominated by Franck--Condon (FC) singlet emission. Lifetime measurements for the complexes of o-xylene and p-xylene with TCNB yielded the two radiative rates (k/sub EQ/ and k/sub FC/) as well as the rate of relaxation from FC to the EQ excited state (k/sub RE/). k/sub RE/ was found to correlate well with viscosity and to be independent of temperature at constant viscosity, indicating that the relaxation process is diffusion controlled.

• Research Organization: School of Chemical Sciences and Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
• OSTI ID: 6243326
• Journal Information: J. Chem. Phys.; (United States), Vol. 75:11
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
COMPLEXES
FLUORESCENCE
HYDROCARBONS
MIXTURES
AROMATICS
DIFFUSION
ELECTRONS
EXCITED STATES
LIFETIME
MEDIUM TEMPERATURE
RELAXATION
SOLVENTS
VERY HIGH PRESSURE
VISCOSITY
DISPERSIONS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
LEPTONS
LUMINESCENCE
ORGANIC COMPOUNDS
400500* - Photochemistry
360603 - Materials- Properties