Physik der kondensierten Materie

, Volume 12, Issue 2, pp 104–130 | Cite as

Spin-lattice relaxation of the O2 molecule-ion in the potassium halides

  • T. G. CastnerJr.
Article

Abstract

An experimental and theoretical study of the spin-lattice relaxation (SLR) of the O2 molecule-ion in the potassium halides has been made. The SLR rate was measured by several methods between 1.32°K and 36°K with a 3 cm. ESR spectrometer. The results indicate a one phonon process with a large anisotropy dominates forT<2°K.T1 is much longer for the magnetic field parallel to the molecular axis. Detailed theoretical calculations indicate a new SLR process, namely phonon-induced libration of the molecular axis, can probably explain the field parallel case. The Van Vleck SLR process can account for the field-perpendicular case.

Keywords

Anisotropy Theoretical Calculation Halide Relaxation Spin Molecular Axis 

Zusammenfassung

Die Spin-Gitter Relaxation (SGR) des O2-Molekül-Ions in den Kalium Halogeniden wurde experimentell und theoretisch untersucht. Die SGR Rate wurde mit verschiedenen Methoden zwischen 1,32°K und 36°K mit Hilfe eines 3 cm-ESR Spektrometers gemessen. Die Resultate zeigen, daß ein Einphononenprozeß mit einer großen Anisotropie fürT<2°K vorherrscht.T1 ist am größten für das Magnetfeld parallel zur Molekülachse. Detaillierte Rechnungen zeigen, daß ein neuer SGR Prozeß, nämlich Phononen induzierte Libration der Molekülachse, wahrscheinlich den Fall des parallelen Feldes erklären kann. Der Van Vleck SGR Prozeß kann den Fall des senkrechten Feldes erklären.

Résumé

Une étude expérimentale et théorique a été faite sur la relaxation spin réseau (RSR) de la molécule O2 dans les halogénures de potassium. On a mesuré le taux de relaxation par plusieurs methodes entre 1.32°K et 36°K avec un 3 cm-ESR spectromètre. Les résultats indiquent qu'un processus à un phonon avec une large anisotropie domine pourT<2°K.T1 est beaucoup plus long pour le champs magnétique parallel à l'axe moléculaire. Des calculs détaillés indiquent qu'un noveau type de RSR processus où la libration de l'axe moléculaire est causé par les phonons peut probablement expliquer le cas du champs parallel. Un processus du type Van Vleck décrit le cas du champs perpendiculaire.

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Copyright information

© Springer-Verlag 1970

Authors and Affiliations

  • T. G. CastnerJr.
    • 1
  1. 1.Department of Physics and AstronomyUniversity of RochesterRochesterUSA

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