From chemistry-request@server.ccl.net Thu Jun 24 10:17:27 1999 Received: from europe.std.com (europe.std.com [199.172.62.20]) by server.ccl.net (8.8.7/8.8.7) with ESMTP id KAA26912 for ; Thu, 24 Jun 1999 10:17:26 -0400 Received: from world.std.com by europe.std.com (STD1.2/BZS-8-1.0) id KAA03409; Thu, 24 Jun 1999 10:13:47 -0400 (EDT) Received: by world.std.com (TheWorld/Spike-2.0) id AA28876; Thu, 24 Jun 1999 10:13:44 -0400 Date: Thu, 24 Jun 1999 10:13:44 -0400 From: jle@world.std.com (Joe M Leonard) Message-Id: <199906241413.AA28876@world.std.com> To: chemistry@ccl.net Subject: re: CCL:MMFF94 validation in Sybyl and Cerius2 Cc: jle@world.std.com "Dr Adrian Stevens" writes: >Has anyone checked the implementation of the MMFF94 force field in both >Sybyl and Cerius2? I cannot speak for Cerius2, but Sybyl's implementation of MMFF94 and MMFF94s pass the validation tests in CCL's archives. The MMFF94 implementation was revalidated recently, as there were additions since last summer. As Tom Halgren requested, this information was sent to him when it was done. I am unaware of any Sybyl user which independently performed the validation tests, but would gladly assist such an effort. I am aware of similar validation being done by Wavefunction and (now) Schrodinger. I assume that any commercial software package offering MMFF94/MMFF94s has examined the validation suites as well. I do not think that the latest MMFF94/MMFF94s information (the various parameters mentioned in Halgren's last email on this) has been made available in the CCL's archive, so it is possible that there are structures which contains features not-well- represented in the validation suites. Such cases might yield small differences due to implementation decisions, but these (I think) would not be significant. I think it is in everybody's best interest to have all implementations of MMFF94/MMFF94s yield "the same" information. If there are questions with particular implementations, please feel free to contact the respective companies - such concerns will be addressed with all resonable dispatch... Joe Leonard jle@world.std.com