<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:'times new roman', 'new york', times, serif;font-size:12pt"><div>Sorry for bringing up the hydroxide ion question again, but are there any hints as to how to place a single hydrogen on the oxygen atom? Can I somehow assign control atoms outside the hydroxide anion as a means of reference for the required ffG43a1.hdb modification? Looks like both methods to attach single protons need some kind of reference (control atoms). Thanks much,</div><div><br></div><div>Marc</div><div style="position:fixed"></div></div></body></html>