Solutions For An Introduction to Medicinal Chemistry Chapter 17 Problem 2Q

The point, at which the first stable conformation of the structure or the molecule has a relatively low energy than that of its starting or initial molecule, is commonly termed as local energy minimum. Since, the structural variations result in low energy changes, energy minimization will cease at this local point.

On the contrary, further variations in structure are carried out in order to cross the saddle to achieve a more stable conformation. This will increase the strain energy of the structure and hence, it will be rejected by the program.

The point of energy, after obtaining the most stable conformation and at which the program has no way to know about an existence of a more stable structure beyond the energy saddle, is termed as the global energy minimum. It is necessary to generate and compare energies of the different conformations of a molecule for identifying their most stable conformation.