\vbox{\line{\hfill \diagram{\xaxis7truecm,0.,180.0,30.0,dihedral angle N--C--C=O; \yaxis7truecm,-282.165,-282.157,0.001,$E$ [Hartree];\nogrid} {\curve{\hpoint0.,-282.164306;\point20.,-282.163403; \point50.,-282.159406;\point70.,-282.157569; \hpoint76.085,-282.157477;\point90.,-282.157919; \point120.,-282.160011;\point140.,-282.160990; \hpoint180.,-282.161409;}} \hfill} \medskip \noindent{\bf Figure~18. \rm Energy profile for the neutral glycine equilibrium shown in Figure~10, obtained from {\it ab initio\/} SCF calculations with the 4-21G basis set.}}