CCL: Gaussian Scan
- From: Tarmo Tamm <tarmo\a/chem.ut.ee>
- Subject: CCL: Gaussian Scan
- Date: Mon, 6 Mar 2006 17:22:54 +0200
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
>
>