Restarting a calculation-chk file or trajectory path

[GJK]

Hi,

When I performed geometry optimization it was cut off suddenly due to a power problem.

I have saved the trajectory(35 images) and also located the chk file from the tmp folder(our jobs are running on the newly implemented mpich paralliesed codes)

Which is best to re run the optimization chk file or the trajectory 35th image with a force component of 0.17 eV/A???

or

is it ok to restart the calculation newly from the chk file???

[Anders Blom]

I would first attempt to start from the last trajectory image, just the geometry. Your checkpoint file might be saved after just a few steps in the SCF cycle, or actually after some steps in the previous geometry, so it might not be worthwhile using it. You will still have a few steps in the force convergence, so it's not worth risking that it's a bad initial state. What you really would like (but isn't implemented) is to have the Hessian matrix from all previous images in the trajectory, but you'll have to wait for ATK 2017 for that feature