W4$\Lambda$: leveraging $\Lambda$ coupled cluster for accurate computational thermochemistry approaches
Abstract
High-accuracy composite wavefunction methods like Weizmann-4 (W4) theory, high-accuracy extrapolated \textit{ab initio} thermochemistry (HEAT), and Feller-Peterson-Dixon (FPD) enable sub-kJ/mol accuracy in gas-phase thermochemical properties. Their biggest computational bottleneck is the evaluation of the valence post-CCSD(T) correction term. We demonstrate here, for the W4-17 thermochemistry benchmark and subsets thereof, that the lambda coupled cluster expansion converges more rapidly and smoothly than the regular coupled cluster series. By means of CCSDT(Q) and CCSDTQ(5), we can considerably (up to an order of magnitude) accelerate W4- and W4.3-type calculations without loss in accuracy, leading to the W4 and W4.3 computational thermochemistry protocols.
Keywords
Cite
@article{arxiv.2312.09062,
title = {W4$\Lambda$: leveraging $\Lambda$ coupled cluster for accurate computational thermochemistry approaches},
author = {Emmanouil Semidalas and Amir Karton and Jan M. L. Martin},
journal= {arXiv preprint arXiv:2312.09062},
year = {2024}
}
Comments
J. Phys. Chem. A 128, 1715-1724 (2024). PDF is CC:BY 4.0