Abstract Conventional CCSD(T) calculations are widely considered as the gold standard for electronic structure theory. However, they become computationally prohibitive for medium- and large-sized molecular systems even with the high-end hardware. In this study, we evaluate the effectiveness of the Grafting-assisted Molecular Tailoring Approach (GMTA) in calculating the energies at the CCSD(T) level of theory. Benchmark calculations are performed on ammonia and water clusters as well as on covalent compounds, utilizing correlation-consistent basis sets. Later, GMTA-CCSD(T) results are compared with conventional (when available) and recently reported FMO2-CCSD(T) calculations. GMTA is found to reproduce energies precisely, with deviations generally in a sub-milli-Hartree range. These findings confirm GMTA as a reliable and computationally efficient alternative for conventional CCSD(T) in the study of medium- and large-molecular systems. Further, such calculations are possible for cases when conventional calculations are not feasible due to hardware limitations.
Sharma et al. (Sun,) studied this question.