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We investigated the particulate organic matter (POM) flux and its stable carbon isotope composition in response to changes in phytoplankton primary production and abiotic environmental affects in mesotrophic Lake Holzmaar. POM fluxes were determined by sediment traps emptied biweekly from 1995 to 2004. Water chemical measurements and meteorological observations were done concurrently. POM fluxes within and directly below the lake's epilimnion were relatively low during winter (

Presents a semiclassical method for simulating the dynamics of nonadiabatic transitions in a discrete-state quantum system coupled to a bath of explicit continuous coordinates. Method's use of a coherent-state formulation of the path integrals for the discrete system whose dynamics is described by spin operators.

Describes a quantum-mechanical Gaussian wave-packet approach to the theoretical description of nuclear motions in a condensed-phase environment. Gaussian density matrices; Microscopic system-plus-bath model; Pump-probe spectroscopy of the reaction center; Model and parameters; Calculation of the emission signal.

Discusses the observability of electronic coherence in electron transfer reactions. Location of large-amplitude oscillations in the electronic occupation probabilities; Conditions under which experiments detecting electronic coherence should be feasible; Feynman-Vernon influence functional formalism.

Coherent wave-packet dynamics on coupled electronic surfaces within a condensed–phase environment is studied. Based on a path integral approach, exact expressions for the case of a one-dimensional reaction coordinate in a donor–acceptor complex are derived. The path integrals over the electronic degree of freedom are further evaluated by applying the golden rule approximation. This procedure allows for an exact treatment of the coupling between solvent or residual molecular degrees of freedom and the reaction coordinate. A detailed picture of the intimate relation between dissipative wave-packet motion and electron transfer is gained also for lower temperatures, strong coupling and slow bath modes, where Redfield type of equations cannot be used. The electron transfer triggered by the coherent vibronic motion leads to a stepwise decay of the population in the donor state. On the acceptor surface the wave-packet dynamics displays a complex interference pattern. Further, it turns out that for a reaction coordinate fast compared to the environmental modes the electronic population dynamics is very sensitive to the initial correlations between bath and reactive mode. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]