Vibrational Analysis

Ali RNAlo... at gmail.com
Sat Jun 21 05:55:49 CEST 2008


Dear CP2K Users,

I wanted to make sure I understood some data I am getting from a
vibrational analysis run type. I am doing the analysis on 4 carbon
atoms of my system and am searching for frequencies in the range of
1-3000. From my output I get the following at the end:

 MS| ITERATION STEP      172
 MS| TRACKED MODE      716.401860cm-1  NOT  CONVERGED
 MS| TRACKED MODE      631.347431cm-1  NOT  CONVERGED
 MS| DAVIDSON ALGORITHM CONVERGED
 MS| TRACKED FREQUENCY (1) IS:  314.918925   cm-1
 MS| TRACKED FREQUENCY (2) IS:  815.338097   cm-1

 
-------------------------------------------------------------------------------
 -                        FREQUENCY AND CONVERGENCE
LIST                        -
        FREQUENCY        MAXVAL CRITERIA        NORM CRITERIA
CONVERGENCE
         5792.243          0.799E-04
0.550E-03               NO
         3748.327          0.317E-04
0.241E-03               NO
         2114.956          0.108E-04
0.581E-04               NO
         2066.005          0.142E-04
0.760E-04               NO
         2009.355          0.973E-05
0.632E-04               NO
         1984.510          0.981E-05
0.613E-04               NO
......

Followed by a whole range of other frequencies all of which are not
converged. (A lot of them are outside the range I requested so I am
assuming thats the default). After the 172nd iteration the davidson
algorithm converges yielding 2 frequencies: 314 and 815 cm^-1. Are the
vibrations associated with these 2 frequencies, the normal modes
associated with those 4 Carbon atoms? These frequencies do not appear
in the Frequency and Convergence List later on though. Am I missing
something?

Any help will be appreciated. Is there any easy way to visualize the
normal modes associated with these frequencies (without having to use
Molden)?

Ali


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