[molpro-user] Problems with the IRC optimization

[yule at iccas.ac.cn]

Dear molpro developers and users:

   I am trying to do an IRC calculation based on the transition state geometry. The TS structure has been fully optimized and has one imaginary frequency.  But, when the IRC calculation is activated, the program gives the following message after the hessian calculation. I have also tried the IRC optimization with the internal coordinate and the error information are the same. 

 IDIR= 1 requested but starting point is not a stationary point. Gradient norm=  0.14D-05  Step length=  0.27D-02
 ? Error
 ? Not a stationary point
 ? The problem occurs in QSDPATH1

The input file:

 ***,Azobenzene calc;
 file,2,azobezene-s0-irc-r12.wfu;
 memory,256,m;
 gprint,civector,orbital;
 basis=6-31g;
 symmetry,nosym;
 geomtyp=xyz;
 geometry={
 24
N     0.414746    0.290435    0.032219 
C     0.216576    0.033654    1.445798 
C     1.254833   -0.634262    2.071852 
C     1.166538   -0.928862    3.424697 
C     0.039156   -0.552379    4.140001 
C    -1.000737    0.118448    3.504674 
C    -0.915303    0.413726    2.154631 
H     2.112629   -0.911848    1.492021 
H     1.968167   -1.446108    3.914438 
H    -0.032173   -0.778759    5.186284 
H    -1.871111    0.407996    4.060646 
H    -1.712901    0.930213    1.657989 
N    -0.456221    0.872084   -0.579909 
C    -1.435267    1.533040   -1.234223 
C    -2.475055    0.823373   -1.852329 
C    -3.466240    1.516048   -2.524160 
C    -3.455395    2.902147   -2.599742 
C    -2.421064    3.595197   -1.985828 
C    -1.414257    2.933590   -1.305931 
H    -2.486957   -0.246830   -1.803633 
H    -4.254856    0.960215   -2.994688 
H    -4.228971    3.426810   -3.124122 
H    -2.391422    4.667104   -2.034849 
H    -0.615918    3.475242   -0.839960  
 }

 int

 {hf;wf,96,1,0;}

 {optg,method=qsdpath,idir=1,maxit=100,saveact=AB-r1.path;print,history;}

  what's wrong with the input? Does this problem caused by the impropriate TS structure?

  Any help would be appreciated.
  Best regards
--
-------------------------
Yu Le
Beijing National Laboratory for Molecular Sciences,
State Key Laboratory of Molecular Reaction Dynamics,
Institute of Chemistry, Chinese Academy of Sciences,
Beijing 100190, People’s Republic of China



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