Helium computation behaves strangely

Dear Tommi,

thanks for your message.
The principal problem in your calculation is the value of crmult: 1.0 is wayy to little for any production result.

Please have a look at the tutorial page on how the basis set should be varied:

http://bigdft.org/Wiki/index.php?title=Basis-set_convergence

Seconldy, for a preiodic calculation as you want to do, the best is always to have a crmult such that the whole box is filled with grid points.
For example, the He20 calculation gives the warning:

- The coarse grid does not fill the entire periodic box

(see at the end of the logfile the list of the warnings.

This means that you are placing the nonzero degrees of freedom only close to the atoms. THis will confine too much the wavefunction and breaks translational invariance, that must be preserved for a 3d periodic calculation.

Do not hesitate in coming back to us should you encounter any problem.

Best

Luigi

Same reason as Question 254943.