VASP Forum

Hello,

I am trying to run calculations with r2SCAN with D4 vdW corrections. I already compiled vasp.6.4.4 with D4 module. To run r2SCAN-D4, I first run D4 module to get vdw parameters needed for VASP and then run VASP and enable D4 corrections. I suppose my total energy should be the sum of r2SCAN and D4 correction, i. e., I can run VASP with r2SCAN to get E1. The run D4 module to obtain E2 and sum the energies: Etot=E1+E2. Finally, this value should be the same as when I ran VASP with D4 correction in it. However, I obtain different results which make me wonder why. I would appreciate it if you could explain what could have been wrong in my calculations.

Thanks,
Mehdi

Hello Mehdi,

Welcome to the VASP forum and thank you for posting. In order to see what is going wrong, can you please share a minimal reproducible example with me that allows me to see the VASP input and output files of the calculations?