Polarizations and assignments of transitions: The method of photoselection

Albrecht, A. C.

doi:10.1016/0022-2852(61)90234-x

Cited by 401 publications

(154 citation statements)

References 30 publications

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“…In this case the theory of photoselection predicts a maximum dichroic ratio AA,,/AA, = 4/3, if the transition moment under observation lies in plane of the circle [27].…”

Section: Discussionmentioning

confidence: 98%

On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis

Junge

Eckhof

1973

FEBS Letters

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“…In this case the theory of photoselection predicts a maximum dichroic ratio AA,,/AA, = 4/3, if the transition moment under observation lies in plane of the circle [27].…”

Section: Discussionmentioning

confidence: 98%

On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis

Junge

Eckhof

1973

FEBS Letters

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“…[67][68][69][70] For the steady-state anisotropy measurements in the fluorometer, Glan-Thompson polarizers were placed in both the excitation and emission light paths. A polarization scrambler was placed immediately behind the polarizer on the emission side to ensure undiscriminated response of the monochromator and optical system to emitted light of either polarization.…”

Section: Methodsmentioning

confidence: 99%

Ground-State Proton-Transfer Tautomer of the Salicylate Anion

et al. 1999

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Solutions of sodium salicylate in anhydrous polar solvents exhibit a weak, temperature-dependent absorption band (λ max ≈ 325 nm) lying in the Stokes gap between the main absorption (296 nm) and the fluorescence band (396 nm, acetonitrile). This weak, longer wavelength absorption band is hardly observable in aqueous solution, but its intensity increases with temperature and increases with polarity in anhydrous organic solvents in the order of ethanol < acetonitrile < dimethyl sulfoxide at room temperature. After correction for solvent thermal contraction, the temperature-dependent absorption spectrum of salicylate in acetonitrile solutions reveals a clear isosbestic point ( 310 ) 2000 M -1 cm -1 ) characteristic of an equilibrium between two salicylate species with band-maximum extinction coefficients of 325 ) 3400 M -1 cm -1 and 296 ) 3586 M -1 cm -1 . In acetonitrile at room temperature (298 K) the concentration equilibrium constant (minor/major) for the interconversion reaction between the two species is K 298 ) 0.11, with ∆H ) 1.6 kcal mol -1 and ∆S ) 0.97 cal‚mol -1 K -1 . The fluorescence lifetime (4.8 ns in acetonitrile) and the shape of the fluorescence spectrum are independent of excitation wavelength. The fluorescence quantum yield for excitation in the long-wavelength shoulder (340 nm) is approximately 60% larger than the yield for excitation in the main band at 296 nm ( 340 ) 0.29, 296 ) 0.18) in acetonitrile at room temperature. These results are consistent with assignment of the shoulder band to the proton-transfer tautomer of the salicylate anion. Electronic structure calculations support assignment of the 325 nm absorption band to the ground-state tautomer (phenoxide anion form) of the salicylate anion. Absorption transition moments for both the normal and tautomer forms are parallel to the emission transition moment, are electronically allowed, and are consistent with 1 L b assignment for both absorbing and emitting transitions. The static dipole moments are in the order of µ(N*) g µ(N) > µ(T*) > µ(T) for the normal (N) and tautomer (T) ground and electronic excited states.

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“…1), the absorption proba bility of the terephthalic acid ester units depends on their molecular orientation relative to the direction of the polarizer (photoselection [7,8 ]). If all the in termediate steps of the photochemical reaction lead ing to the fluorescent end products occur without the participation of rotationally mobile species and with out intermolecular transfer reactions (including exci tation energy transfer), the photoselected initial orientation distribution would be conserved (to a maximum degree) in the final products.…”

Section: Resultsmentioning

confidence: 99%

“…This paper presents a technique to investigate the dependence of photooxidation on wavelength with only a single specimen. Furthermore, the partial con servation of photoselection (principles in [7,8 ]) in the photooxidation of PET is demonstrated by il lumination with linearly polarized light.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence Measurements on the Photooxidation of Poly(ethyleneterephthalate) Films and a Photoselective Effect

Hennecke¹,

Keck²,

Lemmert³

et al. 1989

Zeitschrift Für Naturforschung B

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Polarizations and assignments of transitions: The method of photoselection

Cited by 401 publications

References 30 publications

On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis

On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis

Ground-State Proton-Transfer Tautomer of the Salicylate Anion

Fluorescence Measurements on the Photooxidation of Poly(ethyleneterephthalate) Films and a Photoselective Effect

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Polarizations and assignments of transitions: The method of photoselection

Cited by 401 publications

References 30 publications

On the orientation of chlorophyll‐aI in the functional membrane of photosynthesis

On the orientation of chlorophyll‐aI in the functional membrane of photosynthesis

Ground-State Proton-Transfer Tautomer of the Salicylate Anion

Fluorescence Measurements on the Photooxidation of Poly(ethyleneterephthalate) Films and a Photoselective Effect

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On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis

On the orientation of chlorophyll‐a_I in the functional membrane of photosynthesis