C1 symmetry and minima



 Daniel Kost inquired about pesky imaginary freqs in optimized structures, even
 when these have C1 sym.  It should perhaps be pointed out that there is no
 reason why a C1 structure has to be a minimum; it could be a first-order
 saddle point (a transition state), a higher-order saddle point (a mountain
 top), or not even a stationary point.  Obviously the optimized structures
 he's gettin should be stationary points, and one imag. freq. pins them
 down as transition states.  (Some TS's are "trivial" in that changing
 a
 torsional angle is essentially all that's needed to give a minimum).
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