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--- howto:gaussian [2024/08/12 13:16]
alopis
+++ howto:gaussian [2025/10/17 09:51] (current)
alopis [Easy Gaussian09 and Gaussian16 PBS creation and submission]
@@ Line 53: / Line 53: @@
   source $g16root/g16/bsd/g16.profile
-Then the command **formcheck** should be available for use.
+Then the command **formcheck** should be available for use. Other Gaussian commands should also be available, such as **freqchk** and **chkchk**.
+You can use a **checkpoint file (.chk)** which will allow you to continue with a 2nd (or subsequent) calculation from close to where the initial/previous calculation ended. This is especially helpful for jobs which exceed walltime limits or have stopped for another reason. There is info online including from Gaussian website, these links may be helpful too:
+https://gaussian.com/faq2/
+https://gaussian.com/restart/
+https://gaussian.com/tip4/
+https://www.researchgate.net/post/How-can-I-res...
+Very occassionally  a checkpoint file may be corrupted, so keeping the most recent backup copy of a good checkpoint (.chk) file can be helpful. Otherwise in these circumstances the calculation may need to be started from scratch - or the most recent molecular geometry (the coordinated of all the atoms) could be used from the Gaussian output (.log) file.
+Please **recheck** your molecular **geometry very carefully** to ensure there are no issues - this will result in calculations which take much longer than necessary.

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