Light induced and 'Dark' rotamerization of simple ethers and thioethers in solid neon.

Saturated acyclic hydrocarbons and similar compounds are typically not rigid, but can undergo internal rotations and rearrangements around the individual C-C bonds. As a result, most such compounds occur at room temperature as complex mixtures of conformers, differing by configuration of the carbon atom chain. This rotational isomerism occurs in compounds ranging in size from small discrete molecules such as butane to macromolecules in polymers, such as polyethylene, and is therefore of considerable interest.