Subject: CCL:g98-big displacement during the optimization

From: Jana Precechtelova <[email-masked]>
Date: Tue, 3 Dec 2002 09:09:45 +0100 (MET)

Dear CCL,
does anyone have any idea conserning this problem?:

     I`m trying to perform a geometry optimization of a guanosine-cytidine
     base pair in G98 during which I freeze heavy atoms and optimize
     hydrogens (starting geometry is taken from experiment) but the
     problem is, even in the very first step of the optimization, the
     maximum displacement is terribly big and this remains the same during
     the whole optimization (see below the summary of the first step),
     which finally causes terminating of the opt. because of exceeding the
     number of steps.

1st step:
             Item               Value     Threshold  Converged?
     Maximum Force            0.018320     0.000450     NO
     RMS     Force            0.004048     0.000300     NO
     Maximum Displacement     ********     0.001800     NO
     RMS     Displacement     8.056732     0.001200     NO

last step:
             Item               Value     Threshold  Converged?
     Maximum Force            0.000973     0.000450     NO
     RMS     Force            0.000259     0.000300     YES
     Maximum Displacement     ********     0.001800     NO
     RMS     Displacement     8.058591     0.001200     NO
     Predicted change in Energy=-1.508882D+03
     Optimization stopped.
      -- Number of steps exceeded,  NStep= 171

Thanks for any hint,
Jana Precechtelova

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jana Precechtelova (MSc. student)
NMR Laboratory
National Centre for Biomolecular Research (NCBR)
Faculty of Science, Masaryk University
Kotlarska 2, 611 37 Brno, Czech Republic

email: [email-masked]
phone: +420-5-41129588
fax: +420-5-411 29 506
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~