FIG. 10.

Time spent in the calculation of the lowest excitation energy of a series of formamide-water clusters of increasing size using the aug-cc-pVDZ′ basis set. CIS: time spent in the HF ground state and CIS excitation energy calculations (prior to the CorNFLEx or full CC2 calculation). Loose/standard/tight: time spent in the CorNFLEx algorithm (generation of the CIS(D′)-NTOs and solution of the CC2 equations in the XOS). Full: solution of the CC2 equations in the full canonical basis. All calculations were performed on a single Lenovo nx360 M5 node with 28 cores @ 2.4 GHz and 256 GB memory.