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arXiv · 1410.3505

An Auxiliary-Field Quantum Monte Carlo Study of the Chromium Dimer

Wirawan Purwanto·Shiwei Zhang·Henry Krakauer
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Abstract

The chromium dimer (Cr2) presents an outstanding challenge for many-body electronic structure methods. Its complicated nature of binding, with a formal sextuple bond and an unusual potential energy curve, is emblematic of the competing tendencies and delicate balance found in many strongly correlated materials. We present a near-exact calculation of the potential energy curve (PEC) and ground state properties of Cr2, using the auxiliary-field quantum Monte Carlo (AFQMC) method. Unconstrained, exact AFQMC calculations are first carried out for a medium-sized but realistic basis set. Elimination of the remaining finite-basis errors and extrapolation to the complete basis set (CBS) limit is then achieved with a combination of phaseless and exact AFQMC calculations. Final results for the PEC and spectroscopic constants are in excellent agreement with experiment.

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Wirawan Purwanto, Shiwei Zhang, Henry Krakauer. 2014-10-13. An Auxiliary-Field Quantum Monte Carlo Study of the Chromium Dimer. https://doi.org/10.1063/1.4906829

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