Ab initio calculations on the water dimer show that bond functions gre
atly increase the basis set superposition error (BSSE) at the correlat
ed level. Counterpoise corrections for BSSE mostly undo the effects of
including bond functions, and this holds even for very large basis se
ts. Also, bond functions seriously affect the location of potential mi
nima for the water dimer, at least until counterpoise corrections are
made.