How to guess required memory

Hello everyone. Is there any way to estimate the required memory for a certain energy or optimization calculation?

1 Like

Ideally, the Psi output file should print out an estimate of the memory requirements. What specific method are you asking about?

It’s an optimization calculation with B3LYP-D and 3-21G basis set. I have a big molecule which have 198 atoms and 708 electrons including carbon hydrogen, sulfur atoms and my job is killed without an error message.

What happens if you try B3LYP first, without the -D? Can you post the input here?

I’ve upgraded to 1.5, and the problem is solved. It works fine with b3lyp or b3lyp-d.