. 2017 Dec 16;17(2):22. doi: 10.1007/s11128-017-1792-7

Table 2.

Examples of chemical compounds with their corresponding barrier height and free rotor energy

Compound	$V_{0} (m e V)$	F(meV)	$Δ E_{0} (G H z)$	Regime
o-fluorotoluene	28.14	0.64	20	Intermediate [18]
m-fluorotoluene	2.6	0.66	860	Free Rotor [22]
Lithium acetate			60	[15]
4-Methylpyridine	7.3		120	Intermediate [23]
o-toluidine	86.79	0.66	350	Intermediate [24, 25]

In the third column, the $Δ E_{0}$ is the energy splitting between $(λ = \pm 1, n = 0)$ and $(λ = 0, n = 0)$ levels of the torsional states (or the splitting between $l = 0$ and $l = \pm$ levels of the rotational states, in the limit of the free rotor)