Resonance Raman and molecular orbital studies of the effects of deuteration on the vibrational structure of the p-benzosemiquinone radical anion

Journal Article · Thu Dec 22 04:00:00 EST 1983 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150644a010· OSTI ID:6855977

Schuler, R H; Tripathi, G N.R.; Prebenda, M F; Chipman, D M

Deuterium substitution of the p-benzosemiquinone radical anion results in decreases of 23 and 317 cm/sup -1/ in the vibrational frequencies of its totally symmetric ring stretching (Wilson 8a) and C-H bending (9a) modes as observed by resonance-enhanced Raman methods. Ab initio molecular orbital calculations corroborate the vibrational assignments and predict decreases of a similar magnitude. Both the experimental and theoretical studies show that the bands associated with the CO stretching and C-C-C bending vibrations are affected to only a very minor extent by deuteration, i.e., that there is very little contribution from local modes involving hydrogen motion. The symmetrical ring breathing (1) and C-H stretching (2) modes are not resonance enhanced and not observed in the Raman experiments. Of particular note is the Raman band at the ring stretching frequency of the deuterated radical which is considerably broader than the other lines in H/sub 2/O and partially resolved into two lines in D/sub 2/O. This feature is tentatively interpreted as being due to an accidental near degeneracy with the combination of the 9a and 1 modes. Deuteration of the radical somewhat simplifies its optical absorption spectrum in the region of 400-410 nm indicating that the frequency of the 9a vibration in the excited state is decreased in much the same way as in ground state.

• Research Organization: Univ. of Notre Dame, IN
• OSTI ID: 6855977
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 87:26; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302 -- Organic Chemistry-- Isotope Effects-- (-1987)
400303* -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
ANIONS
AQUEOUS SOLUTIONS
AROMATICS
BENZOQUINONES
CHARGED PARTICLES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPARATIVE EVALUATIONS
COMPUTER CALCULATIONS
DATA
DATA ANALYSIS
DEUTERIUM
DEUTERIUM COMPOUNDS
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXPERIMENTAL DATA
HARTREE-FOCK METHOD
HEAVY WATER
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
IONIZATION
IONS
ISOTOPES
ISOTOPIC EXCHANGE
KINETICS
LABELLING
LASER RADIATION
LIGHT NUCLEI
MAGNETIC RESONANCE
MIXTURES
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PH VALUE
PHOTOCHEMICAL REACTIONS
PHOTOIONIZATION
QUANTITY RATIO
QUINONES
RADIATIONS
RAMAN SPECTRA
REACTION KINETICS
RESONANCE
SAMPLE PREPARATION
SOLUTIONS
SPECTRA
STABLE ISOTOPES
TIME DEPENDENCE
WATER