Effect of the glass-to-fluid transition on excited-state decay. Application of the energy gap law

Journal Article · Thu Oct 09 04:00:00 EDT 1986 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100412a080· OSTI ID:5141056

Lumpkin, R S; Meyer, T J

As observed earlier for related excited states in 4:1 (v/v) ethanol/methanol from 90 to 170 K, emission energies for the metal-to-ligand charge transfer (MLCT) excited states of (Os(bpy)/sub 3/)/sup 2 +/ and (Os(bpy)/sub 2/(CO)(py))/sup 2 +/ shift to lower energies while the lifetimes of the excited states decrease with increasing temperature. From temperature-dependent emission spectral fitting and lifetime data it is concluded that the origin of the effect is in the response of solvent dipole orientations to the changes in electronic configuration between ground and excited states and how it affects the energy gap between the states. For (Os(bpy)/sub 2/(CO)(py))/sup 2 +/, the nonradiative rate constant (k/sub nr/) varies with the energy gap, ln (k/sub nr/) proportional to -E, as predicted by the energy gap law, while for (Os(bpy)/sub 3/)/sup 2 +/ additional complications appear to exist because of contributions to excited-state decay from more than one low-lying MLCT state.

• Research Organization: Univ. of North Carolina, Chapel Hill
• DOE Contract Number: AS05-78ER06034
• OSTI ID: 5141056
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:21; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALCOHOLS
AZINES
BIPYRIDINES
CARBONYLS
CATIONS
CHARGED PARTICLES
COMPLEXES
DATA
DIPOLE MOMENTS
EMISSION SPECTROSCOPY
ENERGY GAP
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
ETHANOL
EXCITED STATES
EXPERIMENTAL DATA
FLUIDS
GLASS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
IONS
LIFETIME
LOW TEMPERATURE
MEDIUM TEMPERATURE
METHANOL
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OSMIUM COMPLEXES
PHASE STUDIES
PYRIDINES
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES