Theoretical ODMR studies in p-terphenyl crystal

L. Hachani*, A. Benfredj Romdhane, M. Mejatty, H. Bouchriha

Laboratoire de Photonique, Polymères et Dispositifs Optoélectroniques

Faculté des Sciences de Tunis, Département de Physique

1060 Tunis, Tunisie

* Corresponding author. E-mail: l_hachani@yahoo.fr

Received : 07 May 2002; revised version accepted : 12 June 2003

Abstract

We used the Johnson Merrifield kinetic schema to perform a theoretical formalism for the dynamic triplet triplet excitons annihilation. A hamiltonian of a microwave field perturbation perpendicular to the static magnetic field was incorporated in the original pilot equation relating to the operator triplets excitons pair density implied in the delayed fluorescence process.

The resolution of the pilot equation, at high magnetic fields, allows us to determine an analytical expression of the delayed fluorescence variation under microwave power. Resonance rays known as ODMR (Optically Detected Magnetic Resonance), at the room temperature, are expected. The presented model specifies positions and intensities according to the intensity and orientation of the static magnetic field with regard to crystallographic axis. Thus, we have proved the existence of two Lorentzian rays in the (bc') plane of the crystal and which coalescent in the direction of resonance.

Keywords: ODMR; Delayed fluorescence; Density-matrix; Resonance.

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