摘要:

A variety of topics is reviewed with an emphasis on assessment of models and discussion of their underlying physical assumptions, rather than on an overview of applications. Different treatments of angular momentum in the Rice-Ramsperger-Kassel-Marcus theory are surveyed and compared for tight and flexible transition states. The influence of angular momentum on thermal reaction rates is examined within the framework of variational transition state theory. The vibrational/rotational adiabatic theory of unimolecular decomposition is discussed. Various models for product energy distributions are summarized. The nature of non-thermal distributions of reactant angular momentum, arising from particular experimental techniques, is examined. A brief discussion of theoretical studies of vibrational/rotational coupling in the reactant and at the transition state is provided. The review attempts to unify advances in the fields of neutral and ion unimolecular decomposition.

ISSN:0144-235X    

DOI:10.1080/01442359109353259

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This review deals with molecular high-resolution spectroscopy based on the quantum beat phenomenon. Applications of the essentially Doppler-free quantum beat technique are presented with special emphasis on the theoretical description. After an historical introduction and a general discussion of interference experiments, we discuss the expressions to describe the time-resolved fluorescence of a molecule following well defined laser excitation. Our general treatment for the characterization of the excited superposition state enables us to demonstrate the versatility of the method by identifying the excited molecular eigenstates with, for example, Zeeman levels or fine- and hyperfine-structure levels. In addition to the spectroscopic applications of quantum beat experiments in determining molecular structure parameters, we address the applications to molecular dynamics and statistical properties of molecular level structures.

ISSN:0144-235X    

DOI:10.1080/01442359109353260

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The method of obtaining collisional energy transfer data for collisions between a highly excited polyatomic and a bath gas from classical trajectories is discussed. The technique yields the mean(-square) energy transferred per collision from a comparatively small (≊500) number of trajectories. Results compare favourably, qualitatively and quantitatively, with experiment for all except the lightest bath gases (where the interaction potential is uncertain). Simple analytical models are also examined. These yield methods of obtaining energy transfer data of practical use in predicting and interpreting falloff data for unimolecular and recombination reactions. It is shown that quantum effects are unimportant for such systems.

ISSN:0144-235X    

DOI:10.1080/01442359109353261

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor