17 research outputs found
Dynamical Jahn-Teller Effect and Berry Phase in Positively Charged Fullerene I. Basic Considerations
We study the Jahn-Teller effect of positive fullerene ions C
and C. The aim is to discover if this case, in analogy with the
negative ion, possesses a Berry phase or not, and what are the consequences on
dynamical Jahn-Teller quantization. Working in the linear and spherical
approximation, we find no Berry phase in C, and
presence/absence of Berry phase for coupling of one hole to an
/ vibration. We study in particular the special equal-coupling case
(), which is reduced to the motion of a particle on a 5-dimensional
sphere. In the icosahedral molecule, the final outcome assesses the
presence/absence of a Berry phase of for the hole coupled to
/ vibrations. Some qualitative consequences on ground-state symmetry,
low-lying excitations, and electron emission from C are spelled out.Comment: 31 pages (RevTeX), 3 Postscript figures (uuencoded
Surprises in the Orbital Magnetic Moment and g-Factor of the Dynamic Jahn-Teller Ion C_{60}^-
We calculate the magnetic susceptibility and g-factor of the isolated
C_{60}^- ion at zero temperature, with a proper treatment of the dynamical
Jahn-Teller effect, and of the associated orbital angular momentum, Ham-reduced
gyromagnetic ratio, and molecular spin-orbit coupling. A number of surprises
emerge. First, the predicted molecular spin-orbit splitting is two orders of
magnitude smaller than in the bare carbon atom, due to the large radius of
curvature of the molecule. Second, this reduced spin-orbit splitting is
comparable to Zeeman energies, for instance, in X-band EPR at 3.39KGauss, and a
field dependence of the g-factor is predicted. Third, the orbital gyromagnetic
factor is strongly reduced by vibron coupling, and so therefore are the
effective weak-field g-factors of all low-lying states. In particular, the
ground-state doublet of C_{60}^- is predicted to show a negative g-factor of
\sim -0.1.Comment: 19 pages RevTex, 2 postscript figures include