From owner-chemistry@ccl.net Mon May 18 08:53:01 2009
From: "Richie Wang richiewangtw]_[gmail.com" <owner-chemistry * server.ccl.net>
To: CCL
Subject: CCL:G: Too many resonance structures in NRT
Message-Id: <-39340-090518080204-18912-ddSxoxPvFUUPAag9Kky0Kg * server.ccl.net>
X-Original-From: Richie Wang <richiewangtw]^[gmail.com>
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Date: Mon, 18 May 2009 19:12:46 +0800
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Sent to CCL by: Richie Wang [richiewangtw(0)gmail.com]
2009/4/26 Nuno A. G. Bandeira nuno.bandeira**ist.utl.pt
<owner-chemistry{=}ccl.net>:
> David Eisenberg david.eisen]~[gmail.com wrote:
>>
>> The job fails because there are more resonance structures than what the
>> computer memory can cope with. =A0I've increased the alloted memory to t=
he
>> maximum, and it crashes still. =A0But I don't need all these structures!=
 =A0I
>> only want to look at the major ones. =A0Is there a way of increasing the
>> threshold, so the program ignores the structures that contribute less th=
an
>> so-and-so, and thus saves on memory? =A0And if it's not possible, any
>> suggestions on what I might try to find the major structures anyway?
>
> You must up the delocalisation threshold. Since the default is 1 kcal/mol
> you could try something like NRTTHR=3D10 or 20 and then go down as you pl=
ease
> to get more resonance structures.
>
> Cheers,
> Nuno
>
>
> --
> Nuno A. G. Bandeira, AMRSC
> Graduate researcher and molecular sculptor
> Inorganic and Theoretical Chemistry Group,
> Faculty of Science
> University of Lisbon - C8 building, Campo Grande,
> 1749-016 Lisbon,Portugal
> http://cqb.fc.ul.pt/intheochem/nuno.html
> Doctoral student .. IST,Lisbon
> --
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>

In my case, I use NRT to calculate the bond order of a compound named
"XK2" in PDB complex "1HVR".
http://www.rcsb.org/pdb/ligand/ligandsummary.do?hetId=3DXK2&sid=3D1HVR ,
It's always halted with the message "Too many resonance structures",
no matter what I try the NRTTHR=3D0.5~50.
Following is the output with G03: (When I change NRTTHR value, but
"Maximum resonance structures" is always the same.)

 NATURAL RESONANCE THEORY ANALYSIS:

 Maximum reference structures :    20
 Maximum resonance structures :    47
 Memory requirements :    5743881 words of   5802280 available

 Warning: Low valence density detected in VALDM; Consider using NRTFDM opti=
on

 FATAL ERROR:  Too many resonance structures, MAXRES =3D    47.

 TOPSTR: Too many resonance structures.
 Error: NBHALT

Could you have any suggestions to my problem? Thanks!