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A method is introduced for simple calculation of charge transfer between very large solvated organic dimers (fullerenes here) from isolated dimer calculations. The individual monomers in noncentrosymmetric dimers experience different chemical environments, so that the dimers do not necessarily represent bulk-like molecules. Therefore, we apply a delocalizing bias directly to the Fock matrix of the dimer system, and verify that this is almost as accurate as self-consistent solvation. As large molecules like fullerenes have a plethora of excited states, the initially excited state orbitals are thermally populated, so that the rate is obtained as a thermal average over Marcus thermal transfers.

A method is developed for computing the direct current and alternating current conductance of molecular wires at small bias. The basic ingredients are: linear response theory, time-dependent density functional theory, imaginary potentials, and a jellium model for the metallic leads. The theory is capable of incorporating the effect of realistic charge distributions in the system and electron- electron correlation. We demonstrate the method on the jellium-C3-jellium system. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 91: 524 -532, 2003

We use Redfield's relaxation theory in the Davies formulation to study primary charge separation reactions in bacterial photosynthesis. The specific model studied is the standard one (spin-boson), with three states for the system, harmonic oscillators for the bath, and linear ohmic system-bath coupling. The Redfield-Davies formulation, which is equivalent to the secular approximation, is Markovian, of second order in system-bath coupling, and is written for the system's density matrix. The approximation does not suffer from any negative probabilities (which appear in the original Redfield approach) and can therefore be used for long-time processes (20 ps or more here). Our results are in line with previous studies, especially to high bath frequencies. They confirm the usefulness of the Redfield-Davies secular approach as a convenient and simple tool for studying system-bath processes. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 87: 254-263, 2002

A solution of the combined Maxwell-Schrodinger equations for the propagation of an ultraviolet (UV) pulse in a sample of model H2 C -like molecules (with only two electronic states), shows a significant increase of the emission at 5-10 harmonics for a thick-density (line integrated density of 50 a.u. 2 ) vs. a thin-density case. The increase is more than two orders of magnitude larger than the expected factor (the ratio of the squared densities) and is due to a "sharpening" effect whereby Rabi oscillations induce a spatially rapidly varying electric field that has very sharp peaks. Equally important, the molecular degree of freedom is shown to exert a strong influence on the emitted radiation so that multiharmonic emission can be controlled by preparing molecules in specific initial wavepackets. c 2001 John Wiley & Sons, Inc. Int J Quantum Chem 81: 260-267, 2001