Background

Non-adiabatic charge transfers are ubiquitous in chemical and electrical processes in condensed phase. Both proton and electron transfer reactions often involve transitions among adiabatic states, and friction due to non-adiabatic effects impacts the electron or hole mobility in solid state. Moreover, emission or absorption of light always includes non-adiabatic transitions. Therefore, an accurate treatment is required of the quantum mechanics of the system considered. The computer simulation of non-adiabatic processes in condensed phase is particularly challenging because of the large number of atoms involved.
The tremendous progress in the field of mixed quantum / classical dynamics in the past decade made it possible to reproduce, predict and understand properties of such processes in biochemical systems comprising several ten thousand atoms. There is a wide range of approaches for the non-adiabatic treatment of the dynamics of a quantum system and a classically described environment as well as for the description of several adiabatic potential energy surfaces at the same time.
There are several reasons why materials sciences could not yet benefit from this progress as much as life sciences and organic chemistry. First, a sufficiently accurate description of more than one adiabatic state in solids using a force field is problematic. Second, due to the complexity of crosslinks between atoms, combining force fields with quantum chemistry to reduce the computational cost of a fully quantum chemical treatment of the system is much harder. Only recently, such mixed quantum / classical potentials could be applied successfully to large solid state systems. Third, excited state density functional theory and semiempirical configuration interaction methods became practical for large systems only very recently. The calculation of inter-surface couplings still is very difficult using these methods.

Motivation and objectives

The purpose of this workshop is twofold. First, it shall provide an opportunity to review and discuss the state of the art and the future directions of computational methodology for describing non-adiabatic charge transfer processes in large systems. Second, it will help combining the recent progress in the methodology for simulation of non-adiabatic charge transfer processes with the recent progress in the methodology for calculating excited states in solid state systems.
There will be a large range of new applications, e.g. computer simulation of light emitting and light sensitive devices, and of charge mobility in new semiconductors, to name just a few.

SB, 12-19-2001