DISTRIBUTION OF CONFORMATIONAL ENERGY MINIMA IN MOLECULES WITH MULTIPLE TORSIONAL DEGREES OF FREEDOM

In this work, the results of a simple model aimed at explaining the ov erall distribution of conformational minima for a chain molecule are p resented. The model assumes that the conformations can be described in terms of rotational isomers associated with each torsion, as done in polymer statistics. Under the model assumptions, the distribution of p otential energy minima can be given a closed, though approximate, form . When compared to a thorough conformational search for aliphatic acid s, carried out using molecular mechanics, the present approach is foun d to account for some of the essential, qualitative features of the di stribution. The results can be viewed as a first step toward the devel opment of rules to assess the completeness of conformational searches, as well as in locating ranges that may require further exploration.