Multireference configuration interaction and coupled cluster study of Gold monosulfide (AuS) including spin–orbit coupling

Abstract

A multireference configuration interaction with the Davidson correction (MRCI + Q) method, including spin–orbit coupling (SOC), was used to calculate the full potential energy curves of the various Ω states of AuS. The spectroscopic constants of the Ω states of AuS were also calculated and compared with the available experimental results. In general, the MRCI + Q+SOC gives qualitatively correct results but does not provide quantitatively accurate results. The unrestricted coupled cluster singles and doubles with perturbative triples (UCCSD(T)) with SOC describe well the molecular properties (bond lengths, vibrational frequencies, and T_e values) of the Ω states. In particular, the bond length of the ground state (Ω = 3/2(²Π_3/2(1)) (2.158 Å) calculated using the UCCSD(T)+SOC is in excellent agreement with the experimental values (2.156 ± 0.002 Å). Both the dynamic electron correlation effect and SOC are crucial to obtain accurate results. We correctly assigned the atomic asymptotes that are correlated with the Ω states and calculated the bond dissociation energies of various Ω states of AuS.

GRAPHICAL ABSTRACT

KEYWORDS:

• Multireference configuration interaction
• CCSD(T)
• relativistic effects
• spin-orbit coupling
• Gold monosulfide

Acknowledgments

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2019R1F1A1063942). This work was supported by the Technology Innovation Program (Grant No. 20009826, Commercialization of Photo definable dielectric for advanced semiconductor packaging) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea). This work was also supported by the Catholic University of Korea, Research Fund, 2020. J. S. Lim acknowledged the fund by the development of electrical apparatus applied Eco-friendly insulation gas and solid material connected 70 kV of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy (MOTIE, Korea), (Grant No. 2019361010001A).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The data that support the findings of this study are available on request from the corresponding author (J. Kim).

Additional information

Funding

National Research Foundation of Korea [grant number NRF-2019R1F1A1063942]; the Ministry of Trade, Industry & Energy (MOTIE, Korea) [grant number 20009826 and 2019361010001A].