Hi Alireza,

you should enable the parallel in the $SYSTEM group ( PARALL=.TRUE.) the default is .false. and the define the number of the CPU needed. Be careful some calculations need more instructions while running in parallel like MEMDDI and memory stuffs.

if you don't want to get into more details i advice you to use GamessQ GUI. It is easy, free and simple and also will do the job for you. ;)

here is the link

https://www.msg.chem.iastate.edu/GAMESS/GamessQ/

cheers

Dear Hamza,

Thank you so much for your answer.

The problem is not about the keyboard in input file.

I installed ORCA and tried to run my files. Unfortunately, only one CPU is involved in DFT calculation.

I think I need to apply some patched to Linux. But I do not know how to do it.

The best