Subject: CCL: Optimising propylbenzene

From: Ian Hovell <HOVELL-.at.-cetem.gov.br>
Date: Wed, 3 Sep 2003 13:03:48 -0300

Dear CCLers,
I have recently been trying to optimise propylbenzene at the B3LYP DFT level
using a 6-31+g(d) basis set. I am using the tight options and an ultrafine
grid in the G98w job route. This works great. But when I include the keyword
option Freq=hindered the job fails claiming a problem in the number of
degrees of freedom (DOF). On inspection on the coordinates of the benzene
ring it can been seen that the C where the propyl group is attached is out
of plane. And thus causing the problem I have with the DOF. I have tried
manually correcting the coordinates and repeating the job but it reverts to
the failing state. Can anyone shed some light on this problem? What do I
need to do to to overcome this problem. I could simply remove the keyword
option "hindered" but this would affect the absolute entropy value which I
am looking for.

TIA
Ian 

Ian Hovell - Ph.D. 
NUCLEO DE MODELAGEM MOLECULAR-NMM 
Centro de Tecnologia Mineral - CETEM 
Ministerio da Cijncia e da Tecnologia- MCT 
Avenida Ipj, No 900 - Cidade Universitaria 
Ilha do Fundco Rio de Janeiro RJ Brasil 
CEP 21941-590 
tel 00 55 (xx) 3865 7344 ou 3865 - 7216 
Fax 00 55 (xx) 22602837 ou 2290-4286 
e-mail hovell-.at.-cetem.gov.br