NWCHEM and DALTON - energy value difference

[kaan karaca]

Dear all,

I am trying to obtain reference values for energy and force for H2 using NWCHEM and DALTON programs. I am using the DFT module of both, implementing pc-4 basis set with Perdew–Burke–Ernzerhof(96) XC. With reduced density and energy convergence tolerance, I only managed to match the energy values up to the 6th decimal digit (also the force values). To my understanding, energy values must match up to the integration error which is in my case significantly lower than the difference between energy values I obtained.  Is there a flaw in my understanding or is the problem with the input files? I attached the input files for both programs (I am using the OPTIMIZE module of DALTON since it also prints the force values).

I am posting this question solely here as DALTON forum seems inactive.

Thank you in advance,

Kaan

[Edoardo Aprà]

Did you check if the number of basis functions (and list of coefficients and exponents) is the same in both codes?

NWChem uses cartesian basis by default, resulting in 156 atomic orbitals. If you add the keyword spherical, the number of AOs decreases to 126.

https://nwchemgit.github.io/Basis.html#-spherical-or-cartesian