Table 19.

Tryptophan Dipeptide, Energy of the Conformers, RMS Deviations ϕ, ψ, χ₁, χ₂ from the Ab Initio Data.

Conformer	Ab initio a	PFF	OPLS-AA/Lb
1	0.00	0.19/6.9	−0.01/7.2
2	0.15	0.56/14.2	0.38/6.5
3	1.30	1.68/16.4	2.16/11.6
4	1.65	2.01/2.1	1.72/4.7
5	2.18	0.94/38.4	2.56/9.8
6	2.22	2.43/6.2	2.05/5.2
7	3.26	2.94/34.9	2.19/49.0
8	2.91	2.94/11.0	2.56/48.2
9	3.41	3.39/3.5	3.48/13.7
RMS errorc	—	0.49/19.4	0.50/24.2

Energies in kcal/mol, angles in degrees.

^aLMP2 cc-pVTZ(-f)//HF6-31G**, ref. 1.

^bRef. 1.

^cPositions of the minima shifted uniformly to achieve the lowest RMS deviation from the ab initio results.