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geometry_optimization_optg [2025/07/25 14:01] – typo dollgeometry_optimization_optg [2025/09/29 09:05] (current) – [Conical Intersection optimization (CONICAL)] doll
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 </code> </code>
  
-This second example optimizes the singlet-triplet intersection in $LiH_2(+)$ (ground state is Singlet, excited state is Triplet).+This second example optimizes the singlet-triplet intersection in $LiH_2(+)$ (ground state is Singlet, excited state is Triplet). Though the optimization works for this example, one has to be careful, as the intersection between states of different symmetry or spin when spin-orbit coupling is not included leads to an energy difference whose first derivative does not vanish at degeneracy. Most geometry optimisation algorithms assume the opposite.
  
 <code - examples/lih2+_S0T0.inp> <code - examples/lih2+_S0T0.inp>