I want to scan potential energy surface for ((CH3+) + O2) reaction, but when I am trying to scan from 3.0 to 1.5A distance the spin as well as charge is also changing at the same time. How can I get correct potential energy surface for this?
Enforce the calculation within one spin, then run the calculation again with the changed spin. Look for geometries close to an intersection of the two PES's and scan for a conical intersection.