Table 2.

Theoretical and Experimental Proton Hyperfine Couplings for Proline Radicals.^a

Radicals	DFT Calculated/Experimental Proton Couplings
	C2-H	C3-H1	C3-H2	Acetyl-CH3
RAD1	3.4G/<5G	-	-
RAD2	-	-	-	26.1G/24Gb (1H)
RAD3	-19.6G/20G -19.6G/20G	16.7G/44G 47.4G/44G	6.6/20Gc 20.5G/20Gd	-

^aTheoretical/Experimental values

^bOnly one coupling from the methyl group is experimentally observed. At 77K the methyl group is locked so to produce one large and two small experimentally not observed couplings.

^cEquilibrium conformation

^dCouplings for a non-equilibrium conformation with dihedral C_carboxyl-C2-C3-C4=23° that gives experimental values.