TITLE:

POST-BLACK BOX METHODS IN COMPUTATIONAL QUANTUM CHEMISTRY: VITAMIN E REGENERATION, ORGANOMETALLIC CATALYSIS, AND TWISTING PLANES (No. 122)

DATE:

Friday, September 22nd, 2006

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Andrew Cooksy, Department of Chemistry, San Diego State University

ABSTRACT:

Density functional and ab initio methods of quantum chemical analysis

have been used to probe the vibrational and chemical reaction dynamics of

three diverse systems: the regeneration reaction sequence of vitamin

E in aqueous solution, the metal-catalyzed conversion of alkyne to

vinylidene, and the internal rotation of biphenyl acetylene. In each

case, additional analysis of these computational results was necessary to

successfully model experimental data. Although the vitamin E reactions

were relatively straightforward to parameterize, they required additional

application of a realistic solvent model, apparently employed for

the first time to model the system free energy in the vicinity of the

reaction transition state for a biochemical process. The metal catalysis

study revealed a reaction surface of surprising complexity, with five

local minimum geometries, and the observed chemical kinetics appear to

be justified by application of the fast equilibrium assumption to at

least one region of the surface. The internal rotation study builds

on our earlier investigation of that molecule by numerical integration

of the vibrational Schroedinger equation, now incorporating basis set

extrapolation and a recent modification to the energy expression to

achieve excellent agreement with existing spectra.

HOST:

John Love

DOWNLOAD: