Getting freq in g98 solvated structures

[Juan Frau Munar <juan (- at -) originqf.uib.es>]

Hi everybody
 I am trying to get with g98 a vibrational analysis of some solvated
 structures, but I have a lot of problems.
 Following I will show the methodology I have been using.
 1) Optimization using the continuum model dpcm
 -- %Chk=pmp1-631s98
  #P SCRF=(DPCM,solvent=1) Opt HF/6-31+G* SCF=(direct,tight)
  ....
 OK, I got the minimised structures
 2) Vibrational analysis
 %Chk=pmp3b-631s98
  #P freq Geom=Allcheckpoint Guess=read HF/6-31+G*
 In this analysis I got always one or two negative frequencies, and
 finally the system starts an optimization and it ends with a non
 converged structure message:
  Item               Value     Threshold  Converged?
  Maximum Force            0.036807     0.000450     NO
  RMS     Force            0.010077     0.000300     NO
  Maximum Displacement     0.159966     0.001800     NO
  RMS     Displacement     0.051859     0.001200     NO
  Predicted change in Energy=-7.193508D-03
 Does anybody know what is the problem?
 Thanks in advance
 ____________________________________
 Juan Frau Munar
 Universitat Illes Balears
 Departament de Quimica
 Palma de Mallorca - 07071
 Baleares. Spain
 email: juan (- at -) originqf.uib.es
 fax:  971 - 173426
 telf: 971 - 173254