. Author manuscript; available in PMC: 2014 Mar 24.

Published in final edited form as: J Comput Chem. 2002 Dec;23(16):1515–1531. doi: 10.1002/jcc.10125

Table 18.

Proline Dipeptide, Energy of the Rotamers, kcal/mol.

Conformer	Ab initio ^a	PFF	OPLS-AA/L^b
Minimum	0.00	1.72	1.78
+60°^c	3.18	3.65	2.86
−60°^c	2.99	2.56	3.87
+180°^c	12.45	10.69	10.12
RMS error^d	—	1.27	1.54

LMP2 cc-pVTZ(-f)//HF6-31G**, ref. 1

Along the N—C—C(O)—N, constrained minimizations.

Positions of the minima shifted uniformly to achieve the lowest RMS deviation from the ab initio results