Application of the multireference equation of motion coupled cluster method, including spin-orbit coupling, to the atomic spectra of Cr, Mn, Fe and Co

作者：Liu Zhebing; Huntington Lee M J; Nooijen Marcel^*

来源：Molecular Physics, 2015, 113(19-20): 2999-3013.

DOI：10.1080/00268976.2015.1063730

• atomic excited states
• coupled cluster
• spin-orbit coupling
• equation of motion coupled cluster

The recently introduced multireference equation of motion (MR-EOM) approach is combined with a simple treatment of spin-orbit coupling, as implemented in the ORCA program. The resulting multireference equation of motion spin-orbit coupling (MR-EOM-SOC) approach is applied to the first-row transition metal atoms Cr, Mn, Fe and Co, for which experimental data are readily available. Using the MR-EOM-SOC approach, the splittings in each L-S multiplet can be accurately assessed (root mean square (RMS) errors of about 70 cm(-1)). The RMS errors for J-specific excitation energies range from 414 to 783 cm(-1) and are comparable to previously reported J-averaged MR-EOM results using the ACESII program. The MR-EOM approach is highly efficient. A typical MR-EOM calculation of a full spin-orbit spectrum takes about 2 CPU hours on a single processor of a 12-core node, consisting of Intel XEON 2.93 GHz CPUs with 12.3 MB of shared cache memory.

• 出版日期2015-10-18