From owner-chemistry@ccl.net Fri Apr 2 15:41:00 2010 From: "Roy Green powergreen-.-gmail.com" To: CCL Subject: CCL: CASSCF problem Message-Id: <-41582-100402150004-18698-ZCu3eBnH8A98O2NDtLFodA^server.ccl.net> X-Original-From: Roy Green Content-Type: multipart/alternative; boundary=001636284bfcac238504834595c7 Date: Fri, 2 Apr 2010 14:59:53 -0400 MIME-Version: 1.0 Sent to CCL by: Roy Green [powergreen%gmail.com] --001636284bfcac238504834595c7 Content-Type: text/plain; charset=ISO-8859-1 Hi, OI and Jamin, Many thanks for your reply. I also guess it is the intruder state problem and MCSCF converged to another state. By inspecting the natural orbitals, I found the converged active orbitals are different from the space I defined in the input. Do you have any suggestion to avoid the intruder states? Thanks again Roy On Fri, Apr 2, 2010 at 1:30 PM, Ol Ga eurisco1 _ pochta.ru < owner-chemistry/./ccl.net> wrote: > > Sent to CCL by: "Ol Ga" [eurisco1]*[pochta.ru] > Dear Roy, > > I suggest you to look closer on convergence process - how much changes the > energy during MCSCF procedure. If you observe significant large oscillation > of energy, your choice of active space does not correspond with chemical > problem of your interest. I think your MCSCF is plagued by intruder states > problem. Hence, you obtain different values of energy. > > MCSCF is very sophisticated method in its applications. In general, Choice > of active space is not an obvious task. The usual advice for newbie in MCSCF > is "Look on orbitals". > > Sincerely, > > Ol Ga> > > --001636284bfcac238504834595c7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, OI and Jamin,
Many thanks for your reply. I also guess it is the int= ruder state problem and MCSCF converged to another state. By inspecting the= natural orbitals, I found the converged active orbitals are different from= the space I defined in the input. Do you have any suggestion to avoid the = intruder states?
Thanks again

Roy



On Fri, A= pr 2, 2010 at 1:30 PM, Ol Ga eurisco1 _ pochta= .ru <ow= ner-chemistry/./ccl.net> wrote:

Sent to CCL by: "Ol =A0Ga" [eurisco1]*[pochta.ru]
Dear Roy,

I suggest you to look closer on convergence process - how much changes the = energy during MCSCF procedure. If you observe significant large oscillation= of energy, your choice of active space does not correspond with chemical p= roblem of your interest. I think your MCSCF is plagued by intruder states p= roblem. Hence, you obtain different values of energy.

MCSCF is very sophisticated method in its applications. In general, Choice = of active space is not an obvious task. The usual advice for newbie in MCSC= F is "Look on orbitals".

Sincerely,

Ol Ga



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