Category: News

Behaviour of DFT-based approaches to the spin– orbit term of zero-field splitting tensors: a case study of metallocomplexes, MIII(acac)3 (M = V, Cr, Mn, Fe and Mo)

Phys. Chem. Chem. Phys., 19, pp.30128-30138 (2017). DOI: 10.1039/C7CP05533a Spin–orbit contributions to the zero-field splitting (ZFS) tensor (DSO tensor) of MIII(acac)3 complexes (M = V, Cr, Mn, Fe and Mo; acac = acetylacetonate anion) are evaluated by means of ab initio (a hybrid CASSCF/MRMP2) and DFT (Pederson–Khanna (PK) and natural orbital-based Pederson–Khanna (NOB-PK)) methods, focusing on the behaviour of DFT-based approaches to the DSO tensors against the valence d-electron configurations of the transition metal ions in octahedral coordination. Both the DFT-based approaches reproduce trends in the D tensors. Significantly, the differences between the theoretical and experimental D (D = DZZ – (DXX + DYY)/2) values are smaller in NOB-PK than in PK, emphasising the usefulness of […]

Analyses of sizable ZFS and magnetic tensors of high spin metallocomplexes

Phys. Chem. Chem. Phys., 19, pp.24769-24791 (2017). DOI: 10.1039/C7CP03850J The fictitious spin-1/2 Hamiltonian approach is the putative method to analyze the fine-structure/hyperfine ESR spectra of high spin metallocomplexes having sizable zerofield splitting (ZFS), thus giving salient principal g-values far from around g = 2 without explicitly providing their ZFS parameters in most cases. Indeed, the significant departure of the g-values from g = 2 is indicative of the occurrence of their high spin states, but naturally they never agree with true g-values acquired by quantum chemical calculations such as sophisticated DFT or ab initio MO calculations. In this work, we propose facile approaches to determine the magnetic tensors of high spin metallocomplexes having sizable ZFS, instead of performing advanced high-field/high-frequency […]

Synthesis and Magnetic Properties of Trioxytriphenylamine Dimers in Di(radical cationic) States

Chem, Eur. J., accepted (2017). DOI: 10.1002/chem.201703220   Three structural isomers of trioxytriphenylamine (TOT) dimers, 4,4”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (4), 3,3”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (5), and 3,4”’-bis(2,2′:6′,2″:6″,6-trioxytriphenylamine) (6) were prepared and their electronic and magnetic properties in the di(radical cationic) states were investigated. The X-ray crystal structure analysis demonstrated that the TOT moieties of all the di(radical cation)s have planar structures similar to that of the structure of the parent TOT radical cation 3+. The UV-vis spectrum of the di(radical cation) showed characteristic absorptions depending on the connecting pattern. Thus, in the long wavelength region (600-900 nm), 4-2+ exhibited strong and broad characteristic absorptions, while compounds 5-2+ and 62+ exhibited weak absorptions. Notably, in the 450-600 […]

Quantum Chemistry on Quantum Computers: A Polynomial-Time Quantum Algorithm for Constructing the Wave Functions of Open-Shell Molecules

J. Phys. Chem. A 120, pp.6459-6466 (2016). DOI: 10.1021/acs.jpca.6b04932 Quantum computers are capable to efficiently perform full configuration interaction (FCI) calculations of atoms and molecules by using the quantum phase estimation (QPE) algorithm. Because the success probability of the QPE depends on the overlap between approximate and exact wave functions, efficient methods to prepare accurate initial guess wave functions enough to have sufficiently large overlap with the exact ones are highly desired. Here, we propose a quantum algorithm to construct the wave function consisting of one configuration state function, which is suitable for the initial guess wave function in QPE-based FCI calculations of openshell molecules, based on the addition theorem of […]