From owner-chemistry@ccl.net Sat Sep  8 13:25:00 2007
From: "hadi behzadi hadi.behzadi**gmail.com" <owner-chemistry-$-server.ccl.net>
To: CCL
Subject: CCL: scan
Message-Id: <-35108-070908121341-14602-eFlu6LBm7LPdrndBuUhQ5w-$-server.ccl.net>
X-Original-From: "hadi  behzadi" <hadi.behzadi++gmail.com>
Date: Sat, 8 Sep 2007 12:13:37 -0400


Sent to CCL by: "hadi  behzadi" [hadi.behzadi*_*gmail.com]
Dear all,

I am trying to do a PES scan for Fe-O distance between 1.75-8 A in heme with one and two water as a axial ligand. I have two problem in this relation as follow:

1- For heme with one water the calculation give me error in 4.1 A because of failure to convergence, the energy profile is good befor this distance.I use SCF(maxcycle=5000) and the B3lyp method with the follow basis sets:
n,o 6-31g*
c,h sto-3g
fe lanl2dz

2- For heme with two water as a axial ligand,one water is fixed, the energy profile is not good due to the break in energy profile in 2.35 and 2.45 A. Here is the obtained energy and used basis sets:

n,o,c,h 3-21g*
fe lanl2dz
Distance   Energy(A.U)
1.75       -2392.47636390
1.85       -2392.48624467
1.95       -2392.48987980
2.05       -2392.49028130
2.15       -2392.48885147
2.25       -2392.48631707
2.35       -2392.48316683
2.45       -2392.58475917
2.55       -2392.58231643
2.65       -2392.57967485
2.75       -2392.57698884 
2.85       -2392.57434438 
2.95       -2392.57179832
3.05       -2392.56938208 
3.15       -2392.56710231   

I really don t underestand what is the problem and any Help would be appreciated.
Regards