CC energy contributions

Dear MRCC Developers,

Is it possible to print out the same-spin and opposite-spin part of the CC correlation energy from your program?


Thank you,
Szymon Śmiga

Dear Szymon,
It depends on what CC method you are interested in. CCSD or higher-order CC methods?

Thank you for quick response.

I'm interested in such of decomposition of correlation energy in the higher-order CC method.

Dear Szymon,
That's easy. Edit mrcc.f, go to subroutine energy, and uncomment the following lines:
write(6,*) 'aa',sum
write(6,*) 'bb',sum
write(6,*) 'ab',sum
and recompile the code. Then you will get the alpha-alpha, etc. contributions to the correlation energy.

Thank you for help.

Szymon Śmiga