Once a potential energy surface (PES) has been generated by the SURF program, it
can be transformed to different representations. The first possibility is a representation
by polynomials, i.e. the POLY program. The representation by grid points
may be altered by the VGRID program, which includes a grid to grid transformation.
Finally the PESTRANS program offers a transformation of the PES
for vibrational structure calculations of isotopologues or Franck-Condon factors.