Bond angle Torsion angle Out-of-plane Van der Waals interaction Bond increment

Table I. Force Constants and Reference Values in the QMFF for Amides A. Bond length E = 2K b b - b02 + 3K b b - b0 3 + 4K b b - b0 4 b0 2K b 3K b 4K b bond Å kcal mol-1 Å-2 kcal mol-1 Å-3 kcal mol-1 Å-4 C-O 1.19201124.2 -2568.6 C-N 1.3983 443.4 1415.3 C-H 1.0934 -780.5 896.3 C-N 1.4416403.9-676.4 650.0 H-N 1.0015 -1300.8 1908.3 C-C 1.5103 -522.3 490.0 H-C 1.0845 -851.3 1040.0 C-C 1.5297 -586.1 758.0

B. Bond angle

E = 2K q q - q0 2 + 3K q q - q0 3 + 4K q q - q0 4 q0 2K q 3K q 4K q angle degrees kcal mol -1 rad-2 kcal mol-1 rad-3 kcal mol-1 rad-4 N-C-O 124.5 115.2 -41.0 -13.3 H-C-O 117.8 54.7 -26.8 0.0 H-C-N 110.4 62.1 -22.0 0.0 C-N-C 111.0 38.0 -8.0 -8.1 C-N-H 117.0 44.6 -9.7 0.0 C-N-H 113.9 54.7 -23.9 0.0 C-C-N 114.3 50.8 -12.6 -11.1 H-C-N 108.9 68.3 3.5 0.0 C-C-O 123.1 66.1 -20.5 0.2 C-C-N 116.9 46.9 -13.1 -10.4 H-N-H 112.9 46.7 -11.3 0.0 C-C-C 108.5 61.9 -11.3 -13.1 C-C-H 107.7 48.3 -34.3 0.0 C-N-C 111.6 47.2 -10.2 -10.1 C-C-N 100.6 62.0 -6.3 -12.7 N-C-N 122.5 123.9 -43.7 -28.9 C-N-C 122.0 90.8 -31.3 -21.1 H-C-H 107.7 51.5 -8.9 -10.8 H-C-C 110.8 52.7 -10.9 -11.3

C. Torsion angle

E = 1K f 1 - cosf + 2K f 1 - cos2f + 3K f 1 - cos3f 1K f 2K f 3K f torsion kcal mol-1 kcal mol-1 kcal mol-1 O-C-N-C 0.830 3.723 -0.050 O-C-N-H -1.882 3.043 -0.373 H-C-N-C 0.334 2.584 -0.401 H-C-N-H -0.008 2.619 -0.090 C-C-N-C 0.020 -0.019 0.013 H-C-N-C 0.031 -0.037 -0.058 C-C-N-H -0.069 -0.011 -0.002 H-C-N-H -0.021 -0.113 -0.175 C-C-C-N 0.108 0.080 -0.287 H-C-C-N -0.025 0.031 -0.207 C-C-N-H -0.915 2.385 -0.238 C-C-C-O 0.063 0.042 0.080 H-C-C-O -0.258 0.002 0.053 C-C-C-N -0.053 0.056 -0.076 H-C-C-N 0.241 -0.013 -0.098 C-C-C-C 0.108 0.080 -0.287 C-C-C-H -0.025 0.031 -0.207 C-C-N-C -0.002 -0.010 0.001 H-C-N-C 0.058 0.051 -0.236 C-C-C-C 0.108 0.080 -0.287 C-C-C-N 0.108 0.080 -0.287 C-C-N-C -0.098 0.109 -0.088 C-C-N-H 0.078 0.108 0.104 N-C-C-O 0.128 0.174 0.129 N-C-C-N -0.127 0.180 -0.126 C-C-N-C -0.753 2.739 0.090 C-C-N-C -0.005 0.007 0.006 N-C-N-H -0.818 0.516 -1.233 O-C-N-C -0.452 1.390 -0.834 H-C-N-C 0.212 1.246 0.047 H-C-C-H -1.152 0.012 -0.179

D. Out-of-plane

E = 2K c c2 2K c out-of-plane kcal mol-1 rad-2 H-C-N-O 42.126 C-N-C-H 1.250 C-C-N-O 44.242 C-N-H-H 0.000 C-N-C-C 4.247 N-C-N-O 49.203 C-N-C-H 0.000

E. Van der Waals interaction

E = e [2rr9 - 3rr6] where r = [r i 6 + r j 6 2] 16 and e = e i ej 12 2 r i r j 3r i 6 + r j 6 r i e i atom Å kcal mol-1 H 1.098 0.013 O 3.535 0.267 C 3.308 0.120 N 4.070 0.106 H 2.995 0.020 C 4.010 0.054

F. Bond increment

E = 332.0 q i q j r ij ; where q i = d ik . Each d ik donates positive charge to the first atom listed and corresponding negative charge to the second atom. d ik bond electrons C–O 0.396 C–N 0.211 H–N 0.440 C–N 0.000 H–C 0.046 C–C 0.000 H–C 0.053 C–C 0.000

G. Bondbond