Dear Iresh,

             In the $Control group, put scftyp=mcscf. Then you also have to make another two groups.First is $drt group and the second one is $det group.In $det group,for full CI calculation put CISTEP = ALDET ,and for occupation restricted multiple active space just put CISTEP = ORMAS.Then in the case of $drt group,put CISTEP = GUGA.

N.B: Look at the INPUT DESCRIPTION of GAMESS.

Thank You Mahesh KUMAR Sit, can you send me an example of that since I am novice  and I have already read but I could not resolve it so far.

Mr. Gallindawatte,

You can focus your attention to the Gamess' manual and corresponding tests, in particular, these examples associated with GS and ES computations. All outputs contains information about total potential energy. You need particular state analysis of your molecule and it photoisomer (S0 and S1) respectively, as well as GS data about molecule containing rotated of 45o bond, if the photoisomerism is associated with cis/trans process of C=C. This can be done manually an dcan be applied to any bond.

Your conical intersection represents the potential energy value of the last state between corresponding S0 (GS molecule) and S1 (ES photoisomer), where in the first case the value should be the maximum of a PES, while for S1 PES this should be the minimum in the energy.

You can use to prepare your inputs by Gabedit (free of charge, ), for example. The runtyp and SCFs (including MCSCF) are explicitly highlighted. The test-files can be processed, including manually corrected by Gabedit as well.

Thank You, Bojidarka B. Ivanova . I check it .