Hi, I want a Conical intersection. For that earlier, I used sf-tddft, and I faced a spin contamination problem. So, now I am thinking of SA-SF-DFT, but I get to know it is not an optimization method. So, my query is how I will do the MECP optimization trajectory or minimum energy pathway using this method.
Please, anyone help me with this? I read the manual also from there it is not that much clear.

There are no gradients for SA-SF-TDDFT, so unless your molecule is very small (so that you could do them by finite difference), that is a non-starter for MECP optimization. SF-TDDFT suffers spin contamination problems that can make it difficult to sort out the states sometimes, or may require human intervention along the way. That is the nature of the beast.

You can perform the SA-SF-DFT single-point calculation using the MECP geometry found by SF-TDDFT. If, fortunately, you happen to find the spin-state energy gap is close to zero (and of course you obtain spin-pure states at the same time).

There is an alternative method which has analytic gradients and almost free of spin-contamination: MRSF-TDDFT, which is implemented in GAMESS.

Thank you, @jherbert and @jxzou-MOKIT for the suggestions.