Torsional Potential Energy Surfaces of Dinitrobenzene Isomers

Figure 8

Torsional PES of orthodinitrobenzene. The conformational energies (in Hartree) of the minima are set to zero. The barriers around () are 0.1989 Ha, and the barriers are 0.0101 Ha at (, ). Different from the previous two isomers, the zero energy point is located at (, ) and the symmetric permutations. The Legendre expansion places the minimum at (), which is closest to the point (, ).