[molpro-user] Geometry specification with Cs symmetry

Jayashree yfpjaya at gmail.com
Wed Mar 18 21:14:03 GMT 2009

Hi all,
I am trying to obtain two states of the methoxy radical - one belonging to
A' and the other belonging to A" symmetry. The optimized geometry
corresponding to A' symmetry is a true minimum and that of A" is a saddle
point. I have the same starting geometry specification for the two states,
but the symmetry of the open shell orbital and thereby the final
wavefunction specification is different in the two cases. The optimisation
is successful for A' state, but in the case of A" state, I get the following

 *Attempt to include non-existent symmetry X
 Because of noorient option, program will
 not align to your requested symmetry elements
 Try again with different symmetry request
 This error can also happen in geometry optimizations that specify
  symmetry-breaking internal coordinates in terms of active variables
 User-specified symmetry elements: X
 Symmetry elements:
 ? Error
 ? Symmetry error
 ? The problem occurs in zmatrix.f:zmat_evaluate*

I believe that in a zmatrix input, MOLPRO automatically reorients the
molecule for the requested symmetry. If I have not specified the noorient
option in my input(below), why does MOLPRO assume it and thereby not

*Input for A" state-*
 q1o=   0.7481460595672777      ,
 q1c=   0.7277119994327224      ,
 q1h1=    1.479915970144683      ,
 q1h2=    1.479915970144683      ,
 q1h3=    1.479915970144683      ,
 h1q1o=    147.9783986150496      ,
 h2q1o=    130.4352205872918      ,
 h3q1o=    130.4352205872918      ,
 dih1=    120.0000000000000      ,
 dih2=    240.0000000000000
Any suggestion would be helpful.
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