CCL:G: SCF convergence problem with M06L functional in Gaussian 09
- From: J C Womack <jw5533{:}my.bristol.ac.uk>
- Subject: CCL:G: SCF convergence problem with M06L functional in
Gaussian 09
- Date: Tue, 1 Mar 2016 11:57:25 +0000
Sent to CCL by: J C Womack [jw5533^-^my.bristol.ac.uk]
It is also worth considering the possibility that the meta-GGA exchange
functional (M06-L) itself is misbehaving.
It is known that certain meta-GGAs (including M06-L) produce
singularities for some electron densities, resulting in SCF convergence
problems. See for example:
Gräfenstein, J., Izotov, D. & Cremer, D. Avoiding singularity problems
associated with meta-GGA (generalized gradient approximation) exchange
and correlation functionals containing the kinetic energy density. The
Journal of Chemical Physics 127, 214103 (2007).
http://scitation.aip.org/content/aip/journal/jcp/127/21/10.1063/1.2800011
Regards,
James
On 26/02/16 05:12, Bulumoni Kalita bulumoni:dibru.ac.in wrote:
> Sent to CCL by: "Bulumoni Kalita" [bulumoni- -dibru.ac.in]
> Dear CCL users,
> I have optimized tetrahedral structure of Pd4 cluster in
(UB3LYP/LANL2DZ) level in Gaussian 09. I wanted to repeat the calculation in
(UM06L/LANL2DZ) level. However, SCF is not converging in this case. Rather it
is fluctuating between to range of values. I have tried using SCF(xqc,
maxcycle=500), opt(maxcycle=500) etc.
>
> Please give your valuable suggestions to overcome this problem.>
>
--
James C. Womack
Email: jw5533_-_my.bristol.ac.uk
Web: http://jcwomack.uk