Table 4. Bonded Interactions: GROMACS Function Type, Permitted Parameter Ranges for Equilibrium Bond Length/Angle, and Corresponding Force Constants.

bond	GROMACS bond funct type	b0/nm	fc/[(kJ/mol)/nm2]
PO4–AM1	1	0.25–0.40	1000–9000
AM1–AM2	1	0.20–0.35	1000–9000
AM1–T1A	1	0.40–0.55	1000–9000
AM2–C1B	1	0.25–0.50	1000–9000

angle	GROMACS angle funct type	a0/deg	fc/(kJ/mol)
PO4–AM1–AM2	2	90–180	5–100
PO4–AM1–T1A	2	90–180	5–100
AM1–T1A–C2A	2	180	5–100
AM2–C1B–C2B	2	180	5–100