Iterative lineshape analysis of quadrupolar echo spectra of a damped CD3 quantum rotor: Preliminary evidence of a navel mechanism of stochastic spin exchange

It is demonstrated that the wealth of information about damped quantum rota tion of CD3 groups, contained in quadrupolar echo spectra, can be fully exp lored in a broad temperature range using a method of iterative analysis of the spectral lineshapes, The recently reported lineshape equation which, ap art from the quantum tunneling and the dissipative Alexander-Binsch terms, contains an additional dissipative term having no classical analog is shown to be capable of describing even subtle details of the spectra of a crysta l of acetylsalicylic acid-CD3 oriented specifically in the magnetic field, Preliminary evidence of the occurrence of this novel dissipative mechanism in the system studied is reported, The results obtained seem to suggest tha t there is no "classical limit" in the dissipative behavior of this system. (C) 2001 Academic Press.