From owner-chemistry@ccl.net Sun Nov 23 12:26:01 2008
From: "Andrea Coletta andrea_coletta*_*libero.it" <owner-chemistry+/-server.ccl.net>
To: CCL
Subject: CCL:G: Hessian Matrix in Internal Coordinates
Message-Id: <-38146-081123121321-24429-a4md6VZ5ISxk60n0Ewg/eQ+/-server.ccl.net>
X-Original-From: Andrea Coletta <andrea_coletta**libero.it>
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Date: Sun, 23 Nov 2008 17:33:33 +0100
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Sent to CCL by: Andrea Coletta [andrea_coletta,,libero.it]
Hi, i'm trying to obtain the Hessian Matrix output in Internal 
Coordinates, from a B3LYP Optimization job with Gaussian03.C02.
My route section is:

#P B3LYP/6-31G* OPT=CalcAll SCRF=CPCM

if I use this with a small molecule (e.g Water), in the log file I find 
something like:

 (Enter /apps/GEN03.C02/g03/l103.exe)

 GradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGradGrad
 Berny optimization.
 Internal  Forces:  Max     0.000010959 RMS     0.000006781
 Search for a local minimum.
 Step number   4 out of a maximum of  20
 All quantities printed in internal units (Hartrees-Bohrs-Radians)
 Second derivative matrix not updated -- analytic derivatives used.
 Trust test= 1.00D+00 RLast= 3.53D-03 DXMaxT set to 4.24D-01
 The second derivative matrix:
                          R1        R2        A1
           R1           0.46509
           R2          -0.00302   0.46509
           A1           0.02978   0.02978   0.16989
     Eigenvalues ---    0.16394   0.46802   0.46812
 RFO step:  Lambda= 0.00000000D+00.

and this is exactly what I want!

It works also with an HF Opt test-job I did with Glycine:

#P HF/3-21G OPT=(ModRedundant,CalcAll) SCRF=pcm
[...]
Force constants in Cartesian coordinates:
                1             2             3             4             5
      1  0.809587D+00
      2  0.000000D+00  0.790299D+00
      3  0.137405D-01  0.000000D+00  0.642144D+00
      4 -0.114527D+00  0.000000D+00 -0.475510D-02  0.644272D+00
      5  0.000000D+00 -0.110951D+00  0.000000D+00  0.000000D+00  
0.621385D+00
      6  0.118871D-01  0.000000D+00 -0.243725D+00 -0.379120D-02  
0.000000D+00
[...]
 Force constants in internal coordinates:
                1             2             3             4             5
      1  0.426378D+00
      2  0.122242D-01  0.472234D+00
      3  0.115444D-01  0.547739D-02  0.471563D+00
      4  0.115444D-01  0.547739D-02  0.574356D-02  0.471563D+00
      5  0.138575D-01 -0.102523D-02 -0.441368D-02 -0.441368D-02  
0.404944D+00
      6  0.737045D-02  0.195704D-03  0.204429D-03 -0.726729D-03  
0.548064D-02

This is very good... the only difference is that it  does'nt specify  
the internal coordinate, and it wrote the Matrix just before enthering 
l103.exe... rather than just after entering, like in the Water 
calculation...

When I try with another molecule a little greater (33 Atoms) it does'nt 
work!!, 
It does'nt print in the log the Hessian matrix, and in the fchk I find 
only the Hessian Matrix in Cartesian coordinates...

I use use the same Route section, and i've tried  a lot of other 
combinations but nothing's working!


 #P B3LYP/6-31G* OPT=CalcAll SCRF=CPCM
or
 #P B3LYP/6-31G* OPT=(Redundant,CalcAll) SCRF=CPCM
or
 #P B3LYP/6-31G* OPT=(ModRedundant,CalcAll) SCRF=CPCM
or
 #P B3LYP/6-31G* OPT=CalcFC
etc. etc.


Maybe the problem is that my system has too many internal degree of 
freedom (96)?
Any Suggestions?


Please Help me!! :-(

Thanks


*****************************
Andrea Coletta
Post-Grad. Student
University of "Tor Vergata"
Rome - Italy
*****************************