Torsional Potential Energy Surfaces of Dinitrobenzene Isomers

Table 1

Coefficients of the Legendre polynomial expansion. For each expansion, we truncate the polynomials once data at the lower energies fit well. The terms marked with “” are zero because of symmetries in the PES or are not used in the model because sufficient agreement was obtained with lower-order terms.

Calculated coefficients (mHa)	Paraisomer	Metaisomer	Orthoisomer
	9.8006	10.7201	10.0467
	−5.6462	−6.0068	0.0000
	0.2811	0.2856	4.8531
	0.0155	0.0136	0.0000
			2.1196
	−5.6462	−6.0068	0.000
	0.2811	0.2856	4.8531
	0.0155	0.0136	0.0000
			2.1196
	0.2850	0.0664	19.2731
			0.0000
			1.0792
			18.4973