Assessing the density functional theory-based multireference configuration interaction (DFT/MRCI) method for transition metal complexes

Abstract

We report an assessment of the performance of density functional theory-based multireference configuration interaction (DFT/MRCI) calculations for a set of 3d- and 4d-transition metal (TM) complexes. The DFT/MRCI results are compared to published reference data from reliable high-level multi-configurational ab initio studies. The assessment covers the relative energies of different ground-state minima of the highly correlated CrF6 complex, the singlet and triplet electronically excited states of seven typical TM complexes (MnO4(-), Cr(CO)6, [Fe(CN)6](4-), four larger Fe and Ru complexes), and the corresponding electronic spectra (vertical excitation energies and oscillator strengths). It includes comparisons with results from different flavors of time-dependent DFT (TD-DFT) calculations using pure, hybrid, and long-range corrected functionals. The DFT/MRCI method is found to be superior to the tested TD-DFT approaches and is thus recommended for exploring the excited-state properties of TM complexes.

Theoretical analysis of excited states and energy transfer mechanism in conjugated dendrimers

“…Several electronic-structure methods, such as SCS-ADC(2), [71] DFT/TDDFT, [72][73][74][75] HF/TDHF, [76] and DFT/MRCI, [34][35][36][37][38][39][40] were used to treat the excited states. The selection of functionals is very critical in the DFT/TDDFT treatments.…”

“…[32,33] In last decades several high-level methods, such as DFT/MRCI, [34][35][36][37][38][39][40] EOM-CC, [41][42][43] CC2, [44,45] ADC(3), [46,47] ADC(2), [48][49][50] TDDFT [51,52] were developed to investigate the excited state of middle-sized molecules while the balance between computational cost and accuracy issue is still far from satisfactions. However, such task is not simple for highly conjugated systems.…”

Intersystem-crossing and phosphorescence rates in fac-IrIII(ppy)3: A theoretical study involving multi-reference configuration interaction wavefunctions

“…57 Somewhat larger MAEs of this method were observed recently in a benchmark study on first-and second-row transition metal complexes where the DFT/MRCI method was found to be superior to the tested time-dependent DFT approaches and was thus recommended for exploring the excited-state properties of transition metal complexes. 58 Use of the original DFT/MRCI parameters in conjunction with the standard orbital selection threshold of 1.0 E h resulted in very long CI expansions with more than 10 8 variables per root in the present case. To cover the measured absorption wavelength range up to about 250 nm, we had to solve for 50 roots in the DFT/MRCI calculations yielding nearly 10 10 freely varying coefficients in total.…”

First Principle Modelling of Materials and Processes in Dye-Sensitized Photoanodes for Solar Energy and Solar Fuels

“…It seems, however, that a similarly strong solvation effect does not apply to metal-centred (MC) or inter-ligand (IL) transitions, which also behave differently with the increase of the HF percentage in the functional [151]. On the other hand, the large size of the systems and the presence of a large number of almost degenerate excited states of different nature [153] have clearly limited the number of correlated wavefunction-based benchmark calculations in the gas phase reported so far [97,151,[154][155][156][157]. Recently, exploiting the efficient implementation of the second order n-electron valence state perturbation theory (NEVPT2) method [90][91][92], in the ORCA program package [93], we have reported state-of-the-art highly-correlated excited states calculations on the low-lying transitions of the N3 dye both in vacuo and water solution, with the aim of shedding light onto the solvation effects on the optical properties of N3.…”