Re: [AMBER-Developers] sqm success/failure on ANP

From: Eric Pettersen <>
Date: Tue, 18 Jan 2011 13:30:59 -0800

On Jan 18, 2011, at 12:55 PM, Qiantao Wang wrote:

> Hi Eric,
> Can't find your input files.

Urg. I guess the reflector stripped those too. I'll be sending them
to you in a separate mail. If anyone else wants to see them let me
know and I'll send them.

>> From what you described, I would guess that your failed
>> calculations may
> have odd number of electrons (i.e. open shell). The PM3 or AM1
> methods in
> SQM cannot deal with such situation.

It's an AM1 calculation. They are both even numbers of electrons (due
to the protonated form being given +1 formal charge relative to the
unprotonated form).

> Did you get any error messages?

The end of the sqm.out file that failed is:


QMMM: Unable to achieve self consistency to the tolerances specified
QMMM: No convergence in SCF after 1000 steps.
QMMM: E = -0.1136E+07 DeltaE = -0.9349E+02 DeltaP = 0.3035E+00
QMMM: Smallest DeltaE = -0.9270E+00 DeltaP = 0.4112E+00 Step = 35


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Received on Tue Jan 18 2011 - 14:00:18 PST
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