Quantum chemistry and energetics in Pu-p-Pu

Saturday, May 7, 2005 - 9:45am - 10:15am
EE/CS 3-180
Roman Osman (Mount Sinai School of Medicine, CUNY)
Joint work with Elena Rusinova and Emmanuel Giudice.

The occurrence of interconversions in backbone angles present
an interesting question as to its origin and frequency. Unlike the rather frequent
BI-BII transitions characterized by the combination backbone angles epsilon
and zeta,
the transition due to an interconversion of the alpha
and gamma
pair is less frequent and in a simulation time span of 15 ns may occur at most
once or twice. Two stable states have been identified ~V the canonical characterized
by alpha/gamma
(-g/+g) and the non-canonical with alpha/gamma
(+g/t). The energetics and the barrier for the interconversion between these
two states are not kn

We have conducted quantum chemical calculations on four Pu-p-Pu
pairs using a PCM to represent the effect of the solvent. The canonical conformations
are lower than the non-canonical and the barriers for the interconversion are
in the range of 7.6 ~V 11.4 kcal/mol. We will discuss these results in the context
of the observed transitions in the ABC simulations.