CCL: correlation between Free energy and NBO data

 Sent to CCL by: "V Suresh Kumar N" [nvskumar123{}]
 Dear CCL subscribers,
 I am studying conformational behavior of a tripeptide showing intramolecular
 H-bond interactions. I explored few set of conformations for it and rank of
 conformations based on free energy data is identified. Stabilization energy
 (E^(2)) of intramolecular interactions (NH...O) is determined using NBO program.
 Interestingly, these values are larger in the conformer which is less stable
 according to free energy data.
 Can any body help in explaining this. Why, the conformer showing strong
 intramolecular charger transfer interaction is not more stable conformer.
 With thanks and regards,