Metastable state

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Written by Grant England AP225, Fall 2011


A metastable state is a state of a system which is stable over one time-scale and unstable over another timescale. It represents a local, but not global, minimum in the energy landscape of the system. In chemistry, a reaction may not take place quickly if the reactants are stuck in a metastable state intermediate between the initial reactants and desired products. In order to progress to the final desired products, the reactants must overcome the activation energy of the reaction to transfer from the metastable state to the stable state. In chemistry, catalysts can be used to lower this activation energy; in biology, enzymes act as the catalysts.

Depiction of metastable state where state 1 is the metastable state, state 2 is the transition state, and state 3 is the stable state. (Image from Wikipedia)

Applications of Metastable States

Lasers use electrical or optical pumping mechanisms to excite electrons into a higher-energy metastable state which can then decay by stimulated emission to generate coherent photons.

Keyword in references:

Flowing Crystals: Nonequilibrium Structure of Foam