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Re^4: A problem in PCM/TDDFT (B3LYP1) Calculation

Arshad Mehmood
acrobat118@hotmail.com

I am using Mercury CSD, Chemcraft and MaSK as Molecular Viewer.
The gemoetry of molecule was not drawn using any Chemical drawing software. I used .cif file. I first tried to optimize using Firefly but it failed to locate stationary point and SCF was not converged.

On Sun Dec 30 '12 3:35pm, sanya wrote
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>>The coordinates which I used to creat input file are the coordinates obtained from the last geometry of Optimized molecule. The Geometry optimization was acrried out using Gaussian 09.

>Probably, you a wrong starting geometry, and optimization ended in the wrong energy minimum, too. Organic compounds cannot look like this. Check 10 times, whether your molecule is correct, and re-optimize (using FireFly, because it is faster).

>Which molecular viewer do you use?

>>It is strange that when I use DIIS Firefly shows error (aforementioned).
>>But using SOSCF i.e. under:
>>$scf EXTRAP=.T. DAMP=.T. SHIFT=.T. RSTRCT=.F. DIIS=.F. DEM=.F. SOSCF=.T. $end
>>It is working normally.

>Anyway, with this geometry, you'll never get correct results.

>>Is the error of DIIS is concerned with the number of processor core?

>No. But when you run FireFly in parallel, it will take less time to see where the error is.

>>I am not running Firefly on a LAN, WAN, or remote. I am running it on a single computer. I have no idea how to utlize all core of single processor during calculations.

>See http://classic.chem.msu.su/gran/gamess/comm_line.html and http://classic.chem.msu.su/gran/gamess/linux_mpich.htmlhttp://classic.chem.msu.su/gran/gamess/linux_mpich.html for the instructions how to run in parallel.
>

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