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Electron Spin−Echo Envelope Modulation Induced by Slow Intramolecular Motion

2003; American Chemical Society; Volume: 107; Issue: 19 Linguagem: Inglês

10.1021/jp027764g

1520-5215

Leonid V. Kulik, И. А. Григорьев, Evgeniy S. Salnikov, Sergei A. Dzuba, Yuri D. Tsvetkov,

Magnetism in coordination complexes

A new type of electron spin−echo envelope modulation (ESEEM) was observed in a three-pulse stimulated echo experiment on nitroxides in a molecular glass. With fixed interval T between the second and the third pulses and variable interval τ between the first and the second ones, it appears in the frequency domain as a broad peak around ∼5 MHz. It is attributed to a sudden change of the EPR resonance frequency due to reorientation of the methyl groups of the nitroxide during the T interval. The rate of the growth of this peak with increasing T reflects the methyl group reorientation rate, which was found to be strongly temperature dependent.