I saved a scratch file from a frequency job. Is there a way I can read it’s computed hessian for a new ts or irc job without rerunning the freq job?
Should be GEOM_OPT_HESSIAN = READ in your $rem. Run Q-Chem with
qchem <-nt Nthreads> -save file.inp file.out scrdir
where scrdir is the name of your scratch directory (in $QCSCRATCH) for the old job.