The EPR Spectrum of the General =C-CX3
Quantum Rotor
A.R. Sørnes
,
N.P. Benetis
Chem. Phys. 226 (1998) 151
Abstract
The quantum mechanical Liouville equation for the general
=C-CX3 rotor is employed
to obtain low temperature EPR spectra exhibiting E-line splittings arising
from the spin-rotational coupling in the hyperfine interaction. Analytic
expression for the low temperature EPR spectrum for the general C3-symmetry
rotor is presented. Analytic spectra for I=1/2, I=1 and I=3/2 nuclei-containing
rotors are discussed in detail. Intensities and positions of first order
transition sidebands are given for the general system and explicitly discussed
for I=1/2 and I=1 systems, with high accuracy determination of tunneling
frequencies and potential twist angles from low temperature experimental
data as possible applications. Anomalous A/E mixing effects on the EPR
spectrum in the transition region between tunneling and stopped rotor conditions
are demonstrated for I=1/2 and I=1 systems and a particular choice of twist
angle.
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