From owner-chemistry@ccl.net Fri Sep 15 12:58:01 2006
From: "Mehmed Zahid Ertem mzertem(a)gmail.com" <owner-chemistry . server.ccl.net>
To: CCL
Subject: CCL:G: Microiterations in ONIOM
Message-Id: <-32548-060915122654-29396-klLzgQ8t/R86nwJL4UpC3w . server.ccl.net>
X-Original-From: "Mehmed Zahid Ertem" <mzertem ~~ gmail.com>
Date: Fri, 15 Sep 2006 12:26:54 -0400


Sent to CCL by: "Mehmed Zahid Ertem" [mzertem%x%gmail.com]
Dear CCLers,

I want to share a problem that I came across during my QMMM optimizations using ONIOM keyword implemented in G03. I don't know whether I made a mistake or the thing I'm asking is not possible.

I have done geometry optimizations by using: 

 ONIOM(B3LYP/3-21G*:AMBER=softfirst)=embedcharge opt=gdiis

and observed the microiterations in the .log file. After these optimizations I tried to find a transition state by using:

 ONIOM(B3LYP/3-21G*:AMBER=softfirst)=embedcharge opt=(ts,noeigen,gdiis,modredundant)

but faced with a extremely slower advance in computations and also noticed that microiterations were not presented in the .log file. Can this (the absence of microiterations) be the reason for increased time of calculation or am I missing something?

Thank you in advance,

Mehmed Zahid ERTEM
Bogazici University
Chemistry Department
MS Student