bond energy variation of methionine‐alanine dipeptide was calculated using HF, DFT and
ab‐initio methods with 6‐31G and 6‐31++G** basis sets. The energy variation for
method shows that as the distance between the two amino acid moieties is increased, the interaction energy between them decreases to negative infinity. The Hartree‐Fock method shows a lack of dissociation point. The interaction energy keeps increasing as the distance between the two amino acid moieties is increased. DFT method using the B3LYP functional describes the bond breaking process more reasonably. After about 4 angstrom, the B3LYP method exhibits the lack of interaction between the two residues.