--time=HH:MM:SS
);--mem=
) (see Monitoring jobs); orquota
. Delete unnecessary files.geom=allcheck
in the route line. It may also be a good idea to use opt=CalcFC
in these situations if it is not too expensive. It is probably not too expensive at the HF or DFT level of theory.--Link1--
. If you have a previous job, then usually Opt=ReadFC
works well, but occasionally Opt=CalcFC
, or rarely Opt=CalcAll
are needed. In these cases, the forces are often converged, but the step sizes are not, and the final output will look likeopt=ef
(if the number of variables is less than 50) or opt=gdiis
(for floppy molecules).gen
from the route line and specify an internal basis set.Opt=ReadFC
or guess=read
or geom=allcheck/modify
) that is not there, either because you did not calculate it previously, or you ran out of disk space or time while running the earlier job and the information needed wasn't written to the checkpoint file. geom=allcheck
in the route section. geom=allcheck
in the route section. ic2
) does not match any standard atomic symbol. This can also happen in a link job if a previous step uses default coordinates (which wipes the z-matrix) and then you try to modify the z-matrix with geom=modify
. The z-matrix variable section is ignored, but Gaussian may attempt to interpret it as basis set information.guess=read
) by carrying out an SCF using the same starting structure, but at a lower level of theory such as HF/STO-3G.SCF=QC
or SCF=XQC
.Opt
instead of FOpt
, but this is not recommended.H3NNN
) that is not in the z-matrix. geom=check
.geom=check
.Opt=CalcFC
. %mem
line. %mem
.--mem=
.geom=modify
, then it interprets the charge/multiplicity line (in the above example, '-2 1') as the title, and then tries to interpret the variable list as the charge/multiplicity line. geom=modify
, but a variable whose value you are attempting to replace is not in the checkpoint file. iop(2/15=4,2/16=2,2/17=7)
to try to avoid program crashing. iop
, or remove altogether.%mem
.%mem
should be at least 1GB less than the value specified in the job submission script. Conversely, the value specified for --mem
in your job script should be at least 1GB greater than the amount specified in the %mem
directive in your Gaussian input file. The exact increment needed seems to depend on the job type and input details; 1GB is a conservative value determined empirically.GAUSS_SCRDIR
to a directory that doesn't exist.mkdir
, or change the definition of GAUSS_SCRDIR
to name an existing directory.