The Distortive Nature of Temperature – A Symmetry Analysis

A new approach to resolve and quantify the effect of temperature on both the average, as well as the instantaneous, structure of generally symmetric molecules is presented. The method employs the efficient continuous symmetry measure, which is shown here to be capable of separating temperature-induced instantaneous disorders from other sources of distortion, such as the Jahn−Teller effect. We demonstrate the potential of the method by studying two highly symmetric molecules: adamantane and the cyclopentadienyl anion and their cationic states. Our results show that although the distortive effect of temperature is significant, it does not mask other distortion effects. Symmetry analysis provides means to quantify the extent of the distortion in each case, and is investigated from a statistical point of view. A major experimental and theoretical challenge is to resolve the Jahn−Teller effect from other environmental effects, such as solvent, solid matrix, concentration, etc. Our results provide a step forward in this direction.