Conformer search with spin-polarized GFN2-xTB

[awvwgk]

Is your feature request related to a problem? Please describe.

Spin-polarization in xTB can have a (minor?) influence on the structures of the conformers, is it possible to enable spGFN2-xTB via tblite for a conformer search in CREST?

Describe the solution you'd like

Probably needs to have either an extra method called spGFN2-xTB or a flag to enable spin-polarization in methods that are supporting it.

[awvwgk]

Should probably be handled here as a "new tblite level":

crest/src/calculator/tblite_api.F90

Lines 135 to 169 in 17a3cf9

	!>--- select parametrization and set up calculator
	tblite%lvl = lvl
	select case (tblite%lvl)
	case (xtblvl%gfn1)
	if (pr) call tblite%ctx%message("tblite> setting up GFN1-xTB calculation")
	call new_gfn1_calculator(tblite%calc,mctcmol,error)
	case (xtblvl%gfn2)
	if (pr) call tblite%ctx%message("tblite> setting up GFN2-xTB calculation")
	call new_gfn2_calculator(tblite%calc,mctcmol,error)
	case (xtblvl%ipea1)
	if (pr) call tblite%ctx%message("tblite> setting up IPEA1-xTB calculation")
	call new_ipea1_calculator(tblite%calc,mctcmol,error)
	case (xtblvl%ceh)
	if (pr) call tblite%ctx%message("tblite> setting up CEH calculation")
	call new_ceh_calculator(tblite%calc,mctcmol,error)
	case (xtblvl%eeq)
	if (pr) call tblite%ctx%message("tblite> setting up D4 EEQ charges calculation")
	call new_ceh_calculator(tblite%calc,mctcmol,error) !> doesn't matter but needs initialization
	case (xtblvl%param)
	if (pr) call tblite%ctx%message("tblite> setting up xtb calculator from parameter file")
	if (allocated(tblite%paramfile)) then
	call tblite_read_param_record(tblite%paramfile,param,io)
	call new_xtb_calculator(tblite%calc,mctcmol,param,error)
	if (allocated(error)) then
	write (stdout,*) 'Could not read tblite parameter file '//tblite%paramfile
	error stop
	end if
	else
	if (pr) call tblite%ctx%message("tblite> parameter file does not exist, defaulting to GFN2-xTB")
	call new_gfn2_calculator(tblite%calc,mctcmol,error)
	end if
	case default
	call tblite%ctx%message("Error: Unknown method in tblite!")
	error stop
	end select

[pprcht]

yes, that should be straightforward. Will do.

[awvwgk]

Thank you

[pprcht]

I'm prepping a larger merge with multiple revisions, probably for next week; don't know if you'd like to wait for that.
But the spin-polarized implementation is ready on my fork: https://github.com/pprcht/crest/tree/experimental
Used as in the tblite app with --spin-polarized