From owner-chemistry # - at - # ccl.net Sun Sep 10 13:50:01 2006
From: "Sherin Alfalah shireen.alfalah^yahoo.com"
To: CCL
Subject: CCL: Energy convergence around conical intersection
Message-Id: <-32511-060910133458-660-ov8zyDGw+p7SJkV9dgawtA||server.ccl.net>
X-Original-From: "Sherin Alfalah"
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
**************************************