Posted by Roland Lindh on December 20, 2005 at 16:12:35:

In Reply to: question posted by tiantian on December 20, 2005 at 14:57:26:

Hi,

the location of a conical intersection require two constraints. 1) the energy of the two states should be identical and 2) they should not interact. For two states of different spin or symmetry condition 2) is trivially fullfilled (the intersection is not conical). If the states are of the same symmetry and spin a second constraint has to be applied to the optimization. This require the use of the non-adiabatic coupling terms. THis term has not been implemented yet (work is in progress). Hence, with the current version of MOLCAS we can not do conical intersections.

-roland

- but
**tiantian***12:02:55 12/21/05*(2)