Wl. Qian et al., A spectroscopically effective molecular mechanics model for the intermolecular interactions of the hydrogen-bonded N-methylacetamide dimer, CHEM P LETT, 315(1-2), 1999, pp. 125-129
An MP2/6-31 + G * calculation of the N-methylacetamide dimer shows that it
has two minimum energy structures, both hydrogen bonded with peptide planes
roughly perpendicular to each other. A complete molecular mechanics optimi
zation of the dimer has been done, using a model for the intermolecular int
eractions consisting of charges, atomic dipoles, and van der Waals interact
ions and the methodology of our spectroscopically determined force field fo
r the intramolecular interactions. The two structures are satisfactorily re
produced, as are their interaction energies, their dipole moments, and, fro
m the point of view of our goal of a spectroscopically accurate force field
, their six intermolecular normal mode frequencies. (C) 1999 Elsevier Scien
ce B.V. All rights reserved.