The Ground State Electronic Energy of Benzene
Janus J. Eriksen, Tyler A. Anderson, J. Emiliano Deustua, Khaldoon Ghanem, Diptarka Hait, Mark R. Hoffmann, Seunghoon Lee, Daniel S. Levine, Ilias Magoulas, Jun Shen, Norm M. Tubman, K. Birgitta Whaley, Enhua Xu, Yuan Yao, Ning Zhang, Ali Alavi, Garnet Kin‐Lic Chan, Martin Head‐Gordon, Wenjian Liu, Piotr Piecuch, Sandeep Sharma, Seiichiro Ten‐no, C. J. Umrigar, Jürgen Gauß
Abstract
We report on the findings of a blind challenge devoted to determining the frozen-core, full configuration interaction (FCI) ground-state energy of the benzene molecule in a standard correlation-consistent basis set of double-ζ quality. As a broad international endeavor, our suite of wave function-based correlation methods collectively represents a diverse view of the high-accuracy repertoire offered by modern electronic structure theory. In our assessment, the evaluated high-level methods are all found to qualitatively agree on a final correlation energy, with most methods yielding an estimate of the FCI value around −863 mEH. However, we find the root-mean-square deviation of the energies from the studied methods to be considerable (1.3 mEH), which in light of the acclaimed performance of each of the methods for smaller molecular systems clearly displays the challenges faced in extending reliable, near-exact correlation methods to larger systems. While the discrepancies exposed by our study thus emphasize the fact that the current state-of-the-art approaches leave room for improvement, we still expect the present assessment to provide a valuable community resource for benchmark and calibration purposes going forward.