Table 2.

Calculations for β-alanine intramolecular condensation reaction^a

methods	parametersb		barrier (kcal/mol)	RMSD with QM TS (Å)	replica ID of approximate TS
NEB	mass-weight	1 k=10	67.83	0.28	9
		2 k=102	55.88	0.19	9
	mass-weight with additional weight on migrating hydrogen	1 k=10	58.83	0.18	10
		2 k=102	54.10	0.18	8
restraint	1 krms=104, kang=102		39.19	0.18	8
	2 krms=105, kang=102		40.16	0.18	8
	3 krms=104, kang=103		54.32	0.10	8
	4 krms=105, kang=104		63.78	0.10	8
constraint	mass-weight	1 kpki= 102	61.52	0.45	9
		2 kpki= 10	48.52	0.13	9
		3 kpki=1	53.45	0.18	9
	mass-weight with additional weight on migrating hydrogen	1 kpki= 102	65.22	0.18	7
		2 kpki= 10	56.43	0.03	8
		3 kpki 1	56.79	0.01	8
		4 kpki=0.1	56.78	0.02	9

^aAll calculations were carried with whole system described in QM at B3PW91/6–31g(d,p) level of theory.

^bUnit for force constant is kcal•mol⁻¹•Å⁻².