Empirical force field calculations (MM2(85)) with atomic point charges calculated from AM1 calculations (MM2/AM1) correctly reproduce AM1 energy surfaces for heterocyclic betaines. The methodology allows extensive conformational analysis of medium to large size molecules by semiempirical calculations (AM1). The interaction energies for the dimerization of betaines are also correctly reproduced. Moreover, the geometry of the stacked dimer is better reproduced by the MM2/AM1 calculations (experimental, 3.29 Å; calculated, 3.37 and 4.07 Å by MM2/AM1 and AM1, respectively). © 1993.
|Journal||Journal of Molecular Structure|
|Publication status||Published - 25 Jan 1993|