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The vibrational relaxation of noble gas-halogen van der Waals clusters has been fertile territory for the development of experimental and theoretical tools for state-to-state dynamics studies. Proceeding through the various combinations of noble gas atoms and halogen molecules, one goes from "simple" direct vibrational predissociation, through sequential relaxation pathways, to the statistical intramolecular vibrational relaxation limit. In some cases the vibrational processes dominate, in others electronically nonadiabatic processes, including chemical reactions, interfere. Thus the noble gas-halogen species provide test cases for most of the dynamical processes available to more "normal" molecules. This review discusses the current state-of-the-art for such studies and points to important problems that remain to be solved.

Scientists obtain their knowledge about the world through one of two major modes of inquiry--observation of naturally occurring phenomena and active experimentation. Both modes of inquiry have been extensively researched in studies of hypothesis testing behaviour and scientific inquiry, the first in studies employing the reception paradigm, the second in studies employing the selection/generation paradigm. The prevalence of both paradigms and their correspondence to well-established modes of scientific inquiry led to the hypothesis that subjects, if allowed, would employ both modes of inquiry. The variables affecting the choice of one mode rather than the other and the transitions between the two modes were expected to shed new light on the process of scientific inquiry. To test this hypothesis, 27 adults and 27 eighth-graders were set three rule-discovery problems, in a computer environment that allowed free transitions between item reception and generation. Item generation was significantly more prevalent in the adult sample, but almost all the adults and approximately half the children employed both modes of inquiry in at least one problem. When both modes of inquiry were employed, the reception mode tended to precede the generation mode. An inverse relationship was observed between item generation and the proportion of positive instances supplied by the environment. Individual inquiry styles were evident in both age groups. These results call attention to the need for a theory incorporating both modes of inquiry as integral components of the inquiry process. They also demonstrate the utility of empirical investigations that let subjects freely choose which mode to employ at any point of the inquiry process.