Dave Feinblum

The Ziman formulation of electrical conductivity is tested in warm and hot dense matter using the pseudo-atom molecular dynamics method. Several implementation options that have been widely used in the literature are systematically tested through a comparison to the accurate, but expensive Kohn–Sham density functional theory molecular dynamics (KS-DFT-MD) calculations. The comparison is made for several elements and mixtures and for a wide range of temperatures and densities, and reveals a… Show more

The Ziman formulation of electrical conductivity is tested in warm and hot dense matter using the pseudo-atom molecular dynamics method. Several implementation options that have been widely used in the literature are systematically tested through a comparison to the accurate, but expensive Kohn–Sham density functional theory molecular dynamics (KS-DFT-MD) calculations. The comparison is made for several elements and mixtures and for a wide range of temperatures and densities, and reveals a preferred method that generally gives very good agreement with the KS-DFT-MD results, but at a fraction of the computational cost. Show less

Lewin and Lieb have recently proven several new bounds on the exchange-correlation
energy that complement the Lieb-Oxford bound. We test these bounds for atoms, for slowly-
varying gases, and for Hooke's atom, finding them usually less strict than the Lieb-Oxford
bound. However, we also show that, if a generalized gradient approximation is to guarantee
satisfaction of the new bounds for all densities, new restrictions on the exchange-correlation
enhancement factor are implied.

Reactions of p-nitrophenylchlorocarbene (PNPCC) with various dibenzo crown ethers produce O-ylides and π-complexes; the reactions can be followed via the spectral signatures of the carbene and the products. The O-ylides form most rapidly, but over time they decay in favor of the more stable π-complexes. Extensive computational studies support and refine appropriate structural and mechanistic conjectures. Reactions of PNPCC with monobenzo crown ethers afford only the spectral signatures of… Show more

Reactions of p-nitrophenylchlorocarbene (PNPCC) with various dibenzo crown ethers produce O-ylides and π-complexes; the reactions can be followed via the spectral signatures of the carbene and the products. The O-ylides form most rapidly, but over time they decay in favor of the more stable π-complexes. Extensive computational studies support and refine appropriate structural and mechanistic conjectures. Reactions of PNPCC with monobenzo crown ethers afford only the spectral signatures of O-ylides; monobenzo π-complexes are either not formed in significant concentrations or are spectroscopically silent. Show less