CCL: DFTB geometries
- From: "Richard Leo Wood" <woodx278::umn.edu>
- Subject: CCL: DFTB geometries
- Date: Tue, 25 Sep 2007 12:05:42 -0400
Sent to CCL by: "Richard Leo Wood" [woodx278!A!umn.edu]
I'm encountering a problem with geometries obtained using DFTB and I am
wondering if anyone else has encountered a similar problem.
I have a series of 12 molecules that I am using to do a validation study. All
of the molcules contian nitrogen and seven of them contain nitrogen and sulfur,
as well as carbon, hydrogen and oxygen.
The problem I am having is that for all seven of the sulfur containing
molecules, I get weird geometries, if they even converge (two of the seven won't
even converge). What I mean by weird is that some of the bond lengths are
REALLY long (like C-C bond of 4 Angstroms or more).
I'm wondering if anyone else has encountered this "problem" using DFTB
and if there is perhaps a work-around to it.