From owner-chemistry \\at// ccl.net Mon Mar 6 10:58:03 2006 From: "Tarmo Tamm tarmo---chem.ut.ee" To: CCL Subject: CCL: Gaussian Scan Message-Id: <-31124-060306102303-7786-a4e1RSOr9LFRD2BhHkgQbg-*-server.ccl.net> X-Original-From: Tarmo Tamm Content-Disposition: inline Content-Type: text/plain; charset=us-ascii Date: Mon, 6 Mar 2006 17:22:54 +0200 Mime-Version: 1.0 Sent to CCL by: Tarmo Tamm [tarmo#%#chem.ut.ee] Hi Opt will initiate a relaxed scan, the "scan" keyword does a restricted scan, these are two different things, consult the manual. You need to define the rotatable group in a way that no dihedral is fixed in place by the hydrogens of the other group. Carbon is ok, as it is placed on the axis of rotation. the following z-matrix will do the trick: c c 1 cc2 h 2 hc3 1 hcc3 h 2 hc4 3 hch4 1 dih4 h 2 hc5 4 hch5 1 dih5 h 1 hc6 2 hcc6 4 dih6 h 1 hc7 6 hch7 2 dih7 h 1 hc8 6 hch8 7 dih8 cc2 1.450000 hc3 1.089000 hcc3 109.471 hc4 1.089000 hch4 109.471 dih4 109.500 hc5 1.089000 hch5 109.471 dih5 109.000 hc6 1.089000 hcc6 109.471 dih6 0.000 35 10.0 hc7 1.089000 hch7 109.471 dih7 109.000 hc8 1.089000 hch8 109.471 dih8 120.000 A rotation of 35 times 10 deg each (it will also calculate the 1st point) Hope it helps Tarmo Tamm University of Tartu On Mar 06, Roger Kevin Robinson r.robinson++imperial.ac.uk wrote: > Sent to CCL by: Roger Kevin Robinson [r.robinson : imperial.ac.uk] > Hi i tried setting each torsion individualy but unsprisingly it did this > > 16 -60.000000 23 15.0000 > 17 60.000000 23 15.0000 > 18 -180.000000 23 15.0000 > A total of 13824 points will be computed. > > which is nt what i want at all and the same problem is still there. > > Do I need to use this keyword > > opt=z-matrix instead of scan > > I have tried this and runs through but it seems to calculate more energy > values than i was expecting and it doesnt put them in a neat little > table like scan does. > > Any reason why it would do this ? > > Is there any way of telling a whole group to rotate ? > > Roger > >