Solid-state Dynamics Research Articles

ChemInform Abstract: Dynamics of Spin Equilibria in Metal Complexes

Publisher Summary This chapter examines the dynamics of spin-equilibrium processes, principally from studies in solutions. The properties of the complexes that are relevant to the dynamics studies are reviewed. The techniques used to observe these rapid processes are also described in the chapter. The chapter presents some aspects of solid-state dynamics and describes some implications for the description of intersystem crossing processes in excited states and for spin equilibria in heme proteins. Many of the complexes that occur in spin equilibrium possess ligands with complicated structures. Trivial abbreviations are used, with structural formulas presented in the table. Generally the complexes are of low symmetry, but in the description of their electronic structure idealized symmetries are assumed and the appropriate term symbols are used accordingly. Some of the concepts, which are used to describe intramolecular spin equilibria, can be extended to the description of these coordination-spin equilibria. Examples include equilibria among four-, five-, and six-coordinate nickel (II) complexes and equilibria involving coordination number changes in iron porphyrin complexes and in heme proteins. Anomalous magnetic susceptibility is the characteristic feature of spin-equilibrium complexes. The Evans nuclear magnetic resonance (NMR) method gives excellent results provided adequate care is taken. There have been very few reports of the Raman spectra of spin-equilibrium complexes.

Quantum transport and solid-state dynamics for Bloch electrons in an electric field

A novel formalism for treating Bloch electron dynamics and quantum transport in electric fields of arbitrary strength and time dependence is presented. In this formalism, the electric field is described through the use of the vector potential; this choice of gauge leads to a natural set of basis functions for describing Bloch electron dynamics in an electric field, even if the field is inhomogeneous . Quantum transport results for Bloch electrons in a spatial homogeneous but arbitrarily time dependent electric field undergoing elastic scattering from randomly distributed impurities (Kohn-Luttinger revisited) are presented; that is, a non-linear “Boltzmann equation” is derived with collision integrals involving not only memory and intracollisional field effects, but also including explicit band-mixing transients such as effective mass dressing and Zener tunneling. The application of this formalism to quantum transport in inhomogeneous electric fields is also addressed; specific applications to problems involving tunneling through “band-engineered” tunneling barriers and impurity scattering in electric fields of arbitrary strength and time dependence are discussed.

Effects of auger recombination process on laser dynamics

The effects of the Auger recombination process on solid-state laser dynamics are analyzed theoretically. The Auger effects on fluorescence lifetime, relaxation oscillations, spatial hole burning, and output powers are given by examining rate equations including the Auger parameter.