Spin Delocalization in Retinals

Spin delocalization over type zero copper.

Hard-ligand, high-potential copper sites have been characterized in double mutants of Pseudomonas aeruginosa azurin (C112D/M121X (X = L, F, I)). These sites feature a small A(zz)(Cu) splitting in the EPR spectrum together with enhanced electron transfer activity. Due to these unique properties, these constructs have been called "type zero" copper sites. In contrast, the single mutant, C112D, ...

Localization-delocalization transition in spin-orbit-coupled Bose-Einstein condensate

We address the impact of the spin-orbit (SO) coupling on the localization-delocalization-transition (LDT) in a spin-orbit coupled Bose-Einstein condensate in a bichromatic potential. We find that SO coupling significantly alters the threshold depth of the one of sublattices above which the lowest eigenstates transform from delocalizated into localized. For some moderate coupling strengths the t...

Topological characterization of delocalization in a spin-orbit coupling system.

We show that wave functions in a two-dimensional ~2D! electron system with spin-orbit coupling can be characterized by a topological quantity—the Chern integer due to the existence of the intrinsic Kramers degeneracy. The localization-delocalization transition in such a system is studied in terms of such a Chern number description, which reproduces the known metal-insulator transition point. Th...

Retinals in a Model Membrane System

Monomolecular films of 9-cis, 11-c/5, 13-cis and all-trans retinal were formed at an air-water interface. Area/molecule and surface potential were measured before, during and after illumina­ tion. The initial quantum yield of the photoisomerization o f 9-cis retinal was 0.25. Irradiation of a retinal monolayer resulted in 30 to 60 m Volt changes in surface potential. Complexation of retinals wi...

Enhancement of spin-dependent hole delocalization in degenerate asymmetric double quantum wells.