geometry optimization in GAMESS

 Dear all,
 I have a question on geometry optimization in GAMESS.
 After the geometry optimization in GAMESS is finished,
 hessian calculation is run automatically to check if
 it's a minimum geometry or not and to get the values
 of the normal vibrational frequencies.
 Sometimes, I've got 1 imaginary vibration frequency,
 and rarely, there are 2 imaginary vibration frequencies.
 These cases clearly means that I do not have a minimized
 geometry.
 My question is, what should I do if I have a geometry
 contains imaginary frequecy?  Do I have to optimize again
 with lower value of OPTTOL(default in GAMESS is 0.0001)
 in STATPT group, or start with different initial geometry
 which has different configuration?  Or, try to use other
 value of maximum/minimu trusted radius??
 Any suggestion/advice/information will be greatly appreciated.
 Many thanks to all the resposes in advence.
 				Sincerely,
 				     Park, TAE-YUN
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 State University of Ghent
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