Theoretical study of third‐row transition metal monofluorides

Abstract

The 5d-metal (excluding La) monofluorides were studied using second order Moller-Plesset (MP2) perturbation theory. The basis set used was Stuttgart/ Dresden (SDD) effective core potentials (ECPs). The ground state multiplicity for these dimers was obtained. The cation and anion of these dimers were also studied at the same level of theory. Relative stability, atomic charges, electron affinity, ionization potential, binding energy (BE), vibrational frequencies, and electronic configuration for these dimers were also obtained. The properties of the neutral dimers were compared with those of their anion and cation. The electronic states of each neutral dimer as well as its ions at their ground state were also defined.

Bond Dissociation Energies of Tungsten Molecules: WC, WSi, WS, WSe, and WCl

“…The next computed state is 1σ 2 1π 4 2σ 2 1δ 1 3σ 2 2π 2 , 4 Δ, lying 0.84 eV higher in energy. This result is consistent with the known ground states of the congeners CrF , and CrCl , and the calculated ground states of MoF, MoCl, MoBr, MoI, and WF . In these diatomics, the highly electronegative character of the halogen leads to a wide separation between the halogen-based 1σ, 2σ, and 1π orbitals (which are primarily halogen ns, npσ, and npπ in character) and the metal-based 1δ, 3σ, and 2π orbitals, which are primarily W 5dδ, 6sσ, and 5dπ in character.…”

“…This result is consistent with the known ground states of the congeners CrF 46,47 and CrCl 48,49 and the calculated ground states of MoF, MoCl, MoBr, MoI, 50 and WF. 51 In these diatomics, the highly electronegative character of the halogen leads to a wide separation between the halogen-based 1σ, 2σ, and 1π orbitals (which are primarily halogen ns, npσ, and npπ in character) and the metal-based 1δ, 3σ, and 2π orbitals, which are primarily W 5dδ, 6sσ, and 5dπ in character. The large separation leads to a reduced orbital interaction between the two centers, making the WCl molecule more ionic than the other species considered here.…”

Investigation of Molecular Iridium Fluorides IrFn (n=1–6): A Combined Matrix‐Isolation and Quantum‐Chemical Study

“…This assignment is in accordance with the fundamental gas‐phase frequency of IrF at 650 cm −1 deduced from electronic band spacings [14k] . Our CCSD(T) calculations predict a strong stretching frequency for this species at 632.6 cm −1 , slightly lower than the above values obtained in neon matrix (Table 1), but significantly blue‐shifted in comparison to the reported value (575.0 cm −1 ) obtained previously at second‐order Moller‐Plesset (MP2) perturbation theory level [14m] …”

“…Optimized structures are shown in Figures 2, 3 and S3, and vibrational frequencies are compiled in Table 1 and Tables S5–S10 in Supporting Information. The bond length of diatomic IrF calculated by Kalamse and co‐workers at the MP2 level was 192.8 pm, [14m] while our value of 186.1 pm at the CCSD(T) level is closer to the 185.1 pm obtained experimentally by laser induced fluorescence and dispersed fluorescence spectroscopy [14k] . Siddiqui reported that IrF 2 has a bent structure with Ir−F bond lengths of 189.7 pm at B3LYP DFT level with a scalar relativistic PP using unspecified basis sets [14n] .…”