For 10 points, name these unobservable entities whose energy content equals that of the reactants plus the activation energy, represented by the peaks on a reaction coordinate.
The "nitroalkane anomaly" results when charge differences make these entities imbalanced. The vibrational partition function can be used to find the characteristic loose vibrational mode of these entities, which can move either perpendicular to or along the diagonal on square plots that represent them as dots. One model of these entities is based on minimizing the one-way (*) flux coefficient. These entities have one imaginary frequency and can be found using the Synchronous Transit-Guided Quasi-Newton method. Differences between them determine the product ratios of conformers. Double daggers represent these saddle points of potential energy surfaces, which resemble the species closest in free energy according to Hammond's postulate. For 10 points, name these unobservable entities whose energy content equals that of the reactants plus the activation energy, represented by the peaks on a reaction coordinate.
The "nitroalkane anomaly" results when charge differences make these entities imbalanced.
transition states [accept activated complexes; accept TST; do not accept intermediates]