Hi.
I am working on some organic molecules and performing simulations with the help of Gaussian software. But my jobs are not getting converged within 24 hours of walltime. I am producing a checkpoint file for molecules. But unable to read and work on it. Can anyone please suggest me how to work with checkpoint files. As these checkpoint files can be considered as an input file for my next simulation.
Thanks in advance.
Shreyas Parbat , It depends on information you need from checkpoint file, but in general you can use the following two keywords:
Geom=AllCheckpoint : Reads the molecular geometry, charge, multiplicity and title from the checkpoint file. This is often used to start a second calculation at a different level of theory.
Guess=Read : Reads the initial guess from the checkpoint file. If the basis set specified is different from the basis set used in the job which generated the checkpoint file, then the wave function will be projected from one basis to the other. This is an efficient way to switch from one basis to another.
Note that, When a calculation is started using information from a checkpoint file, the calculation results will be placed in the exact same checkpoint file, overwriting the original checkpoint file. Thus it is always a good idea to make a backup copy of the checkpoint file.
Regards,
Shreyas Parbat , It depends on information you need from checkpoint file, but in general you can use the following two keywords:
Geom=AllCheckpoint : Reads the molecular geometry, charge, multiplicity and title from the checkpoint file. This is often used to start a second calculation at a different level of theory.
Guess=Read : Reads the initial guess from the checkpoint file. If the basis set specified is different from the basis set used in the job which generated the checkpoint file, then the wave function will be projected from one basis to the other. This is an efficient way to switch from one basis to another.
Note that, When a calculation is started using information from a checkpoint file, the calculation results will be placed in the exact same checkpoint file, overwriting the original checkpoint file. Thus it is always a good idea to make a backup copy of the checkpoint file.
Regards,
Dear Shreyas,
Check this webpage for restarting jobs using chk and read-write files:
https://gaussian.com/restart/
Also, you can also restart optimizations this way (opt=restart):
https://gaussian.com/opt/
For using your chk files, you need to specify where those files are in the new input files that you want to run. If the chk files are in the same folder where you run the new calculations, adding %chk=FILENAME.chk should work. If the chk files are in a different folder (i.e. scratch folder of your HPC cluster), you need to specify the path where your chk files are (i.e. %chk=\Scratch\User\FILENAME.chk
Hope it helps!
Dear shreyas
you can generate the new .chk file from the log file.
follow those steps
1 open the log file
2 go to edit then mos (molecular orbitals) - new mos - generate new check point file - set model and basis set - click on generate
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