# CCL: Energy convergence around conical intersection

*From*: "Sherin Alfalah" <shireen.alfalah ~~
yahoo.com>
*Subject*: CCL: Energy convergence around conical intersection
*Date*: Sun, 10 Sep 2006 13:34:57 -0400

Sent to CCL by: "Sherin Alfalah" [shireen.alfalah-*-yahoo.com]
Dear CCL users,
We are trying to run energy calculations for some points around a conical
intersection. I am facing some problems in convergence for the excited state. To
reach MCSCF convergence, we try to read some molecular orbitals of other close
points or to run the energy calculations for the excited state with more weight
of the ground state for example "0.1 or 0.2". In the conical
intersection region, reading different vectors may lead to different stationary
points with different energies. I am a bit confused about the most proper way
to have convergence. Shall it be the choice of method that gave the lowest
energy or what? How can I know that I am not over shooting the minimum?
We are using GAMESS, I am wondering if the results we have are due to chemical
reasons or some artificial results of GAMESS software.
I think that having more weights of the ground state, is reasonable since the
points are within the conical intersection area?
I am wondering about the most proper way to obtain convergence? and also if some
one has any experience or know some tricks that may be useful to obtain
convergence? Also, any information or discussion for this issue would be highly
appreciated.
Thanks in advance.
**************************************
Sherin Alfalah
PhD Student
Theoretical Chemist
Chemistry Department
AlQuds University
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