Covalent Potential Energy Terms Covalent U,+U1 bond angle +u tU orion bond ∑ k,(b-b)2 bonds bond angle ∑k(0-20 bond angles z mproper dihedral ∑k improper dihedrals 2(- torsion ∑k1+ cos(no-6) torsions Brooks et al, J. Comput. Chem. 4: 187-217 (1983)Covalent Potential Energy Terms UCovalent = U bond + U angle bond + Uimproper dihedral + U torsion 2 U bond = ∑ 1 kb (b − b 0 ) bonds 2 2 U angle bond = ∑ 1 kθ (θ − θ ) bond angles 2 0 Uimproper dihedral = ∑ 1 improper dihedrals 2 k Φ ( Φ − Φ 0 ) U torsion = ∑ 1 kφ[1 + cos( n φ − δ )] torsions 2 Brooks et al., J. Comput. Chem. 4: 187-217 (1983) 2