Temperature dependence of the lowest excited singlet-state lifetime of all- trans -. beta. -carotene and fully deuterated all- trans -. beta. -carotene

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.457337· OSTI ID:5295533

Wasielewski, M R; Johnson, D G ^[1]; Bradford, E G; Kispert, L D ^[2]

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1. Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (USA)
2. Department of Chemistry, University of Alabama, Tuscaloosa, Alabama 35486 (USA)

A 4 ps, 450 nm laser pulse was used to electronically excite all-{ital trans}-{beta}-carotene and all-{ital trans}-{beta}-carotene-{ital d}{sub 56} in 3-methylpentane. The transient absorption spectra of these molecules were measured as a function of temperature down to 20 K. In all cases the 400--500 nm electronic absorption band of each carotene bleaches and a new absorption band near 560 nm appears immediately upon excitation. These bands recover with single exponential kinetics: {tau}=8.1{plus minus}0.5 ps for all-{ital trans}-{beta}-carotene, and {tau}=10.5{plus minus}0.6 ps for all-{ital trans}-{beta}-carotene-{ital d}{sub 56} at 294 K. These recovery times increase by about a factor of 2 in glassy 3-methylpentane, and are nearly independent of temperature from 100 to 20 K. The weak dependencies of the lowest excited single-state lifetime of all-{ital trans}-{beta}-carotene on deuteration and temperature are discussed in terms of nonradiative decay mechanisms within carotenoids.

• DOE Contract Number: W-31-109-ENG-38; FG05-86ER13465
• OSTI ID: 5295533
• Journal Information: Journal of Chemical Physics; (USA), Vol. 91:11; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CAROTENOIDS
ABSORPTION SPECTRA
RADIATIONLESS DECAY
PHOTOSYNTHETIC REACTION CENTERS
ENERGY TRANSFER
DEUTERATION
DEUTERIUM
ELECTRONIC STRUCTURE
EXCITED STATES
LIFETIME
LOW TEMPERATURE
MEDIUM TEMPERATURE
TEMPERATURE DEPENDENCE
VERY LOW TEMPERATURE
VIBRATIONAL STATES
CHEMICAL REACTIONS
DE-EXCITATION
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PIGMENTS
SPECTRA
STABLE ISOTOPES
TERPENES
400500* - Photochemistry