Localization of energy on the molecular scale
- Univ. of California, San Diego, CA (United States)
We discuss the spontaneous localization of vibrational energy in translationally invariant anharmonic chains at finite temperatures. In addition to the familiar energy-driven coherent mechanisms, which are rapidly degraded by thermal fluctuations, we identify the entropy-driven phenomenon we call {open_quotes}stochastic localization{close_quotes}, within which we include a number of characteristics of soft anharmonic oscillators in thermal equilibrium. Principal among these are a tendency for soft oscillators to spend more time at higher energies than comparable harmonic oscillators, and for high-energy fluctuations in soft oscillators to persist for longer times than lower-energy fluctuations, leading to a tendency for energy fluctuations to be organized into {open_quotes}bursts{close_quotes} separated by intervals of relative quiet. We illustrate the effects of stochastic localization on a bistable impurity embedded in a chain of soft oscillators by comparing it to an impurity embedded in a harmonic chain. Effects on transition rates at a given system energy can be quite dramatic.
- Research Organization:
- Argonne National Lab., IL (United States)
- OSTI ID:
- 569636
- Report Number(s):
- CONF-9705121--; ON: DE98000902
- Country of Publication:
- United States
- Language:
- English
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