Deactivation of the S{sub 1} state of a water-soluble porphyrin cation in a complex with DNA studied by the method of picosecond absorption spectroscopy

Journal Article · Wed Aug 31 04:00:00 EDT 2005 · Quantum Electronics (Woodbury, N.Y.)

DOI:https://doi.org/10.1070/QE2005V035N08ABEH004086· OSTI ID:21470816

Sazanovich, Igor' V; Chirvonyi, V S ^[1]

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1. Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, Minsk (Belarus)

The deactivation of the excited S{sub 1} state of 5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin (H{sub 2}TMPyP4) in a complex with DNA is studied by the methods of kinetic absorption spectroscopy for different concentration ratios r of porphyrin and DNA base pairs. It is found that, when the DNA bound porphyrin is assumed to be in a monomer (non-aggregate) state (r=1:30), the S{sub 1} state of porphyrin excited by high-power picosecond pulses is rapidly deactivated, which is manifested as an additional decay component with the decay time 200-250 ps. This effect is interpreted as singlet-singlet annihilation of excitation indicating the presence of sites on the DNA surface with a higher local concentration of porphyrin molecules. The decrease in the relative content of DNA in solution down to r=1:3 further accelerates the deactivation of the S{sub 1} state of porphyrin and causes the hypsochromic shift of its absorption spectrum due to the formation of stack-like porphyrin aggregates along the DNA surface. It is assumed that the additional component with the decay time 44{+-}7 ps observed in the decay curve of the S{sub 1} state is caused by the annihilation of excitation in porphyrin aggregates. (laser applications and other topics in quantum electronics)

• OSTI ID: 21470816
• Journal Information: Quantum Electronics (Woodbury, N.Y.), Journal Name: Quantum Electronics (Woodbury, N.Y.) Journal Issue: 8 Vol. 35; ISSN 1063-7818
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ABSORPTION SPECTROSCOPY
ANNIHILATION
AQUEOUS SOLUTIONS
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
CONCENTRATION RATIO
DEACTIVATION
DECAY
DIMENSIONLESS NUMBERS
DISPERSIONS
DNA
ENERGY-LEVEL TRANSITIONS
EXCITATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HOMOGENEOUS MIXTURES
INTERACTIONS
IONS
MIXTURES
MOLECULES
MONOMERS
NUCLEIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARTICLE INTERACTIONS
PORPHYRINS
PULSES
SOLUTIONS
SPECTRA
SPECTROSCOPY