HYPOCHROMISM AND OTHER SPECTRAL PROPERTIES OF HELICAL POLYNUCLEOTIDES

Journal Article · Fri Sep 01 04:00:00 EDT 1961 · Journal of the American Chemical Society (U.S.)

DOI:https://doi.org/10.1021/ja01478a017· OSTI ID:4837951

Rhodes, W

Exciton interaction in a double-stranded helical polymer, such as a homogeneous polynucleotide, leads to a splitting of each excited electronic energy level of the monomer into two exciton bands of energy levels. Consideration of the selection rules derived from zeroth-order functions shows that for double-stranded polynucleotides pi yields pi * transitions are allowed to, at most, one exciton level of each band, both polarized perpendicularly to the helix axis; whereas, n yields pi * transitions are allowed only to one level of the upper band, that being polarized parallel to the helix axis. Examination of the spectral properties of the four constituents of deoxribonucleic acid (DNA) reveals that although exciton bands probably exist in regions of spectral overlap, there should be isolated energy levels lying below the main exciton bands. These levels may act as localized energy traps during excitation propagation through the helix. In order to treat the problem of hypochromism, it is necessary to use first-order functions. An equation is developed which takes into account the effect of exciton interaction and dispersion-force interaction on the oscillator strength of the helix. Application of this equation to a helical, double-stranded polyadenylic acid having the configuration of DNA indicates that perturbation resulting from dispersion-force interaction among the bases can account for the observed hypochromism. (auth)

• Research Organization: Florida State Univ., Tallahassee
• Sponsoring Organization: USDOE
• NSA Number: NSA-15-030644
• OSTI ID: 4837951
• Journal Information: Journal of the American Chemical Society (U.S.), Journal Name: Journal of the American Chemical Society (U.S.) Vol. Vol: 83; ISSN JACSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ADENOSINE
ADENYLIC ACID
BEHAVIOR
CHEMISTRY
DISPERSIONS
DNA
ENERGY
ENERGY LEVELS
EQUATIONS
EXCITATION
INTERACTIONS
LEVELS
MATHEMATICS
MOLECULES
NUCLEIC ACIDS
ORGANIC ACIDS
OSCILLATIONS
OSCILLOGRAPHS
POLARIZATION
POLYMERS
RIBONUCLEIC ACID
SPECTRA