Dear all,

I am trying to run a SAPT2+(3)dMP2/aTZ calculation (Gold standard according to J. Chem. Phys. 2014, 140, 094106) on a small test system (methane dimer) using Psi4 1.0rc. Since I cannot upload the input and output files that I get (apparently new users are not allowed to do that), here are only the important parts. I have requested “energy(‘sapt2+(3)dmp2’)” in the input. The calculation runs without errors, however, when it comes to computation the SAPT interaction energy contributions, I get the following header:

//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>//

// SAPT2+(3)DMP2 //

//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<//

This looks fine, however, then the following appears after the information for the Laplace Denominator:

```
SAPT0
Ed Hohenstein
6 June 2009
```

The problem is that now the program only calculates the SAPT0 terms. I have computed already SAPT2(CCD)dMP2/aTZ interaction on the same system and that works perfectly fine, so the additional terms are computed. Could there be an error in the code regarding that? Is it known and already fixed in the current version of Psi4? I am happy for any input in that regard. If somebody would want to see the actual input I use and the output I get, I am happy to send it per mail.

Thank you already in advance for your help.

Best,

Robert