Picosecond excited state dynamics and excitation transport in solution and on surfaces

Technical Report · Sun Nov 01 04:00:00 EST 1987

OSTI ID:5259101

Anfinrud, P A

Time correlated single photon counting was employed in studies of excitation transport (ET) depolarization in 2- and 3-dimensional disordered systems. Reduced concnetrations ranged up to )approximately)3 in ethylene glycol solutions of DODCI (3-dimensioanal system) and )approximately)5 in Langmuir-Blodgett monolayers containing octadecyl rhodamine B (2-dimensional system). Discrepencies between experiment and current ET theories (3-body Gochanour-Andersen-Fayer andor 2-particle Huber) are small when artifacts due to reabsorption, dimerization (and concomitant trapping), solvent reorganization, and molecular reorientation are minimized or correctly modeled. Discrepancies persist in glycerol solutions of DODCI; they are attributed to orientational correlation between chromophores. The orientational correlation apparently arises from 3-dimensional liquid glycerol structure and extends to )approximately)R/sub O/. An optical shot noise limites detection scheme was developed which enabled pump-probe transient absorption studies of submonolayer rhodamine 640 adsorbed on fused silica and ZnO. The ground state recovery dynamics on silica are coverage dependent due to excitation trapping by dye aggregates. In contrast, the recovery on ZnO is significantly faster and essentially coverage independent. This provides strong evidence for efficient dye )yield) semiconductor nonradiative excitation decay

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5259101
• Report Number(s): IS-T-1291; ON: DE88007621
• Country of Publication: United States
• Language: English

Related Subjects

656002* -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALCOHOLS
ALKENES
AMINES
CHALCOGENIDES
CORRELATIONS
DATA ANALYSIS
DEPOLARIZATION
DETECTION
DISPERSIONS
ENERGY LEVELS
ETHYLENE
EXCITED STATES
FLUORESCENCE
GLYCOLS
HYDROCARBONS
HYDROXY COMPOUNDS
LUMINESCENCE
MINERALS
MIXTURES
NEUTRAL-PARTICLE TRANSPORT
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOTODETECTORS
PHOTON TRANSPORT
RADIATION TRANSPORT
RESOLUTION
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SOLUTIONS
SPECTROSCOPY
SURFACES
TIME RESOLUTION
TIMING PROPERTIES
TRANSPORT THEORY
TRAPPING