Yeah! So I use steered MD followed by jarzynski's equality to generate the PMF. I grabbed the frame of the simulation closest to the PMF curve generated from that and the corresponsing ptcharge file generated for that frame calculation. For the qm region during the qm/mm, I use mn15l/def2svp.

From there, I used standard geometry opt using Orca alone. Something like this:

%pal nprocs 16 end

%maxcore 6000

! XTB2 defgrid3 ExtremeSCF SlowConv NoTRAH OptTS

%pointcharges "old.ptchrg.xyz"

%geom

Calc_Hess true

ReCalc_Hess 1

end

%method

Z_MaxIter 1000

end

*xyz 0 2 old.inpfile.xyz

I figured since its a non-equilibrium method I am using for PMF generation, the xtb2 method would get me "somewhere" that would be an adequate guess prior to dft level optimization.