Paramagnetic Resonance Absorption in Naphthalene in Its Phosphorescent State

Hutchison, Clyde A.; Mangum, B. W.

doi:10.1063/1.1744621

Cited by 250 publications

(58 citation statements)

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“…After a delayed interval, Hutchison and Mangum in 1958 [59], and van der Waals and de Groot in 1959 [60] succeeded in successfully observing the expected ESR splitting, in oriented molecules in an isomorphic crystal lattice, and in glass solvents, by these researchers respectively. This interval of 12 years added to the delay in the general acceptance of the triplet state assignment.…”

Section: Photophysics Of the Triplet Statementioning

confidence: 99%

From Jabłoński To Femtoseconds. Evolution of Molecular Photophysics

Kasha

1999

Acta Phys. Pol. A

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A presentation is given, with retrospective commentary, on the experimental and theoretical contributions to key steps in the evolution of the framework of contemporary molecular photophysics from the Jabłoński Diagram to femtosecond range excitation phenomena. The distinctive features of polyatomic molecules separating their behavior from atomic and diatomic molecules are emphasized. Justification is given for the statement that spin-orbital coupling with its relativistic component commonly domi- nates the molecular excitation dynamics of light-(low-Z)-atom molecules.The paper deals with single-photon, single-molecule excitations. Some examples of single-photon, multi-molecule and multi-photon, single-molecule excitation phenomena are listed. A selection of these is made to illustrate the prevalence of femtosecond excitation modes.

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Section: Photophysics Of the Triplet Statementioning

confidence: 99%

From Jabłoński To Femtoseconds. Evolution of Molecular Photophysics

Kasha

1999

Acta Phys. Pol. A

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“…spectra of orbitally nondegenerate hydrocarbon triplet states can be understood (1,2) on the basis of a Zeeman interaction and a second-order tensor tern1 independent of the field. T h a t is in terms of the spin Hamiltonian T h e zero field splitting tensor G is due primarily (13)(14)(15) …”

Section: Discussionmentioning

confidence: 99%

Spin–spin interactions in polyphenyls

Gardner¹

1967

Can. J. Chem.

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An attempt has been made, with some success, to interpret the zero field splitting parameters for the triplet states of molecules such as the polyphenyls where the subunits are weakly coupled and the molecules are probably nonplanar. The method used was a semi-empirical exciton theory, applied in particular to biphenyl and 1,3,5-triphenylbenzene. I n these two cases it is found that structure information, in particular the angle between rings, obtained by this method is in good agreement with electron diffraction data.Canadian Joutnal of Chemistry. Volume 45, 1707 (1967) The early electron spin resonance (e.s.r.) studies of Hutchison and Mangum (I) and van der IVaals and de Groot (2) have stimulated considerable experimental and theoretical interest in the triplet states of organic molecules. One of the main theoretical concerns has been the correlation of the zero field splitting parameters D and E mith~molecular structure.For the excited triplet states of aromatic molecules such as benzene and naphthalene, as well as various methvlenes and nitrenes which have triplet ground states, the theoretical predictions (3-7) based on molecular orbital descriptions are in good agreement with what is observed experimentally.T h e purpose of the present study is t o investigate the use of an exciton description for the calculation of zero field splitting parameters. This type of model is-widely used in the description of the optical properties of molecular crystals (8, 9). T h e same approach has achieved some success in the description of molecules in which the subunits are weakly coupled, such as linear polyenes (10, 11) and polyphenyls (8, 12).We develop the theory initially to discuss the e.s.r. results of triplet biphenyl and triphenylbenzene. Some discussion of the a~~l i c a t i o n of the model t o molecules such A A as triphenylene is also given.IPresent address: Defence Chemical, Biological and Radiation Laboratories, Ottawa, Canada. DISCUSSIONT h e e.s.r. spectra of orbitally nondegenerate hydrocarbon triplet states can be understood (1,2) on the basis of a Zeeman interaction and a second-order tensor tern1 independent of the field. T h a t is in terms of the spin Hamiltonian T h e zero field splitting tensor G is due primarily (13-15) to the first-order effect of the dipolar spin-spin interaction. In this approximation G is an average over the wave function where and ri, is the vector joining the electrons. (11) BiphenylWe consider biphenyl to consist of two weakly interacting phenyl groups. l4o(A) and 341(A) are the wave functions representing the ground state and first excited triplet state of phenyl group A respectively.T o first order we may then write the ground and lowest triplet molecular wave function as Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.202.233.140 on 05/11/18For personal use only.

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“…While in Canada I had been interested in the effects of static magnetic fields on triplet state spectra and energy transport and had attempted some optical measurements using electron paramagnetic resonance magnets. The electron paramagnetic resonance of the naphthalene triplet had been measured recently (6) to yield the zero-field splittings and spin-density distributions, and it dispelled any doubts that existed about the triplet nature of the long-lived emitting states of organic molecules. The electron paramagnetic resonance experiments used conventional approximately 10-kG magnets, bringing the triplet splittings into the microwave region.…”

Section: Molecular Crystals and Magnetic Field Effectsmentioning

confidence: 99%

On a Research Rollercoaster With Friends

Hochstrasser

2006

Annu. Rev. Phys. Chem.

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Paramagnetic Resonance Absorption in Naphthalene in Its Phosphorescent State

Cited by 250 publications

References 10 publications

From Jabłoński To Femtoseconds. Evolution of Molecular Photophysics

From Jabłoński To Femtoseconds. Evolution of Molecular Photophysics

Spin–spin interactions in polyphenyls

On a Research Rollercoaster With Friends

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