  We developed an interface program between a program suite for an automated
search of chemical reaction pathways, GRRM, and a program package of
semiempirical methods, MOPAC. A two-step structural search is proposed as an
application of this interface program. A screening test is first performed by
semiempirical calculations. Subsequently, a reoptimization procedure is done by
ab initio or density functional calculations. We apply this approach to ion
adsorption on cellulose. The computational efficiency is also shown for a GRRM
search. The interface program is suitable for the structural search of large
molecular systems for which semiempirical methods are applicable.
