__How to run a W3-F12 calculation with Molpro and MRCC:__

To run a W3-F12 calculation follow these steps:

1. Run a W2-F12 calculation using the molpro script available here.

2. Run the following calculations with molpro or MRCC:

CCSD(T)/cc-pVDZ [MRCC input file]

CCSDT/cc-pVDZ and CCSDT(Q)/cc-pVDZ [MRCC input file]

CCSD(T)/cc-pVTZ [MRCC input file]

CCSDT/cc-pVTZ [MRCC input file]

3. Extrapolate the CCSDT–CCSD(T) difference from the cc-pV{D,T}Z basis sets.

4. Calculate the CCSDT(Q)–CCSDT difference with the cc-pVDZ basis set.

5. W3-F12 = W2-F12 + T–(T)/cc-pV{D,T}Z + (Q)/cc-pVDZ

Please contact me in case you need any additional information.

1. Run a W2-F12 calculation using the molpro script available here.

2. Run the following calculations with molpro or MRCC:

CCSD(T)/cc-pVDZ [MRCC input file]

CCSDT/cc-pVDZ and CCSDT(Q)/cc-pVDZ [MRCC input file]

CCSD(T)/cc-pVTZ [MRCC input file]

CCSDT/cc-pVTZ [MRCC input file]

3. Extrapolate the CCSDT–CCSD(T) difference from the cc-pV{D,T}Z basis sets.

4. Calculate the CCSDT(Q)–CCSDT difference with the cc-pVDZ basis set.

5. W3-F12 = W2-F12 + T–(T)/cc-pV{D,T}Z + (Q)/cc-pVDZ

Please contact me in case you need any additional information.