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

• Main Authors: Zhebing Liu, Huntington, Lee M.J., Nooijen, Marcel
• Format: Text
• Language: unknown
• Published: Taylor & Francis 2015
• Subjects: Space Science; 29999 Physical Sciences not elsewhere classified; FOS Physical sciences; Molecular Biology; Physiology; FOS Biological sciences; 39999 Chemical Sciences not elsewhere classified; FOS Chemical sciences; Immunology; FOS Clinical medicine; 19999 Mathematical Sciences not elsewhere classified; FOS Mathematics; Plant Biology; Orca
• Online Access: https://dx.doi.org/10.6084/m9.figshare.1477840.v2; https://tandf.figshare.com/articles/Application_of_the_multireference_equation_of_motion_coupled_cluster_method_including_spin_8211_orbit_coupling_to_the_atomic_spectra_of_Cr_Mn_Fe_and_Co/1477840/2

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.