Ground State Wave Function Of Cu Research Articles

EPR study of Cu 2+-doped tetraaqua-di(nicotinamide)Co(II) saccharinate single crystals

The electron paramagnetic resonance spectra of Cu 2+ impurities in [Co(nicotinamide) 2(H 2O) 4](saccharinate) 2 single crystals have been studied at ambient temperature in three mutually perpendicular planes. The angular variation of the spectra shows that the Cu 2+ ion substitutes the Co 2+ site in the lattice. The EPR spectra of Cu 2+ ions are characteristic of tetragonally elongated octahedral site. The spin-Hamiltonien parameters were obtained from the single crystal EPR analysis. The ground-state wave function of Cu 2+ ion in the lattice has been constructed.

Variable temperature EPR spectra of Copper (II) ions in kainite crystals

X-band electron paramagnetic resonance (EPR) studies on divalent copper ions embedded in KMgClSO 4·3H 2O single crystals have been performed at low temperature (123 K). The angular variation of the EPR spectra reveals the presence of two Cu 2+ sites, which have different orientations. The spin-Hamiltonian parameters of this six-coordinated cupric ion have been evaluated from the EPR spectra at 123 K. The forbidden lines due to Δ m I=±1 transitions are observed in between allowed transitions. The temperature variation EPR studies have also been performed both for a single crystal and a polycrystalline sample. The ground state wavefunction of Cu 2+ ions has been estimated and is found to be an admixture of d 3 z 2 − r 2 and d x 2 − y 2 . The temperature variation of the EPR spectra reveals that Cu 2+ ions exhibit dynamic Jahn–Teller effect. From the polycrystalline EPR data, the temperature dependent magnetic susceptibilities are evaluated and discussed.

EPR studies of Cu2+-doped bis(saccharinato)bis(pyridine)zinc(II) single crystals

The electron paramagnetic resonance spectra of Cu 2+ impurities in bis(saccharinato)bis(pyridine)zinc(II) single crystals have been studied at room temperature in three mutually perpendicular planes. The angular variation of the spectra indicates the substitution of the host Zn 2+ with Cu 2+ . Two magnetically inequivalent sites for Cu 2+ have been observed. The spectra were fitted to the rhombic spin Hamiltonian. The spin Hamiltonian parameters and the molecular orbital coefficients were evaluated for the two sites. The ground-state wave function of Cu 2+ ion in the lattice has been constructed.

A quantitative description of the ground-state wave function of Cu(A) by X-ray absorption spectroscopy: comparison to plastocyanin and relevance to electron transfer.

To evaluate the importance of the electronic structure of Cu(A) to its electron-transfer (ET) function, a quantitative description of the ground-state wave function of the mixed-valence (MV) binuclear Cu(A) center engineered into Pseudomonas aeruginosa azurin has been developed, using a combination of S K-edge and Cu L-edge X-ray absorption spectroscopies (XAS). Parallel descriptions have been developed for a binuclear thiolate-bridged MV reference model complex ([(L(i)(PrdacoS)Cu)(2)](+)) and a homovalent (II,II) analogue ([L(i)(Pr2tacnS)Cu)(2)](2+), where L(i)(PrdacoS) and L(i)(Pr2tacnS) are macrocyclic ligands with attached thiolates that bridge the Cu ions. Previous studies have qualitatively defined the ground-state wave function of Cu(A) in terms of ligand field effects on the orbital orientation and the presence of a metal--metal bond. The studies presented here provide further evidence for a direct Cu--Cu interaction and, importantly, experimentally quantify the covalency of the ground-state wave function. The experimental results are further supported by DFT calculations. The nature of the ground-state wave function of Cu(A) is compared to that of the well-defined blue copper site in plastocyanin, and the importance of this wave function to the lower reorganization energy and ET function of Cu(A) is discussed. This wave function incorporates anisotropic covalency into the intra- and intermolecular ET pathways in cytochrome c oxidase. Thus, the high covalency of the Cys--Cu bond allows a path through this ligand to become competitive with a shorter His path in the intramolecular ET from Cu(A) to heme a and is particularly important for activating the intermolecular ET path from heme c to Cu(A).

Spectroscopic Studies of Cu2+ Ions Doped in KZnClSO4 � 3H2O Crystals

EPR, optical absorption and infrared spectral studies have been performed on Cu 2+ ions doped in KZnClSO 4 . 3 H 2 O single crystals. The room temperature single crystal EPR spectra reveal the presence of two magnetically inequivalent Cu 2+ sites. The spin-Hamiltonian and molecular orbital parameters have been evaluated. The optical absorption spectrum at room temperature exhibits a broad band centred at 11900 cm -1 which has been assigned to the transition |3z 2 - r 2 > → |xz, yz>. The ground state wavefunction of Cu 2+ ions has been estimated and found to be predominantly |3z 2 - r 2 > with a slight admixture of |x 2 - y 2 >. The infrared spectra of KZnClSO 4 . 3 H 2 O have been also studied in the wavelength range 4600 to 400 cm -1 . The observed bands are assigned to the low symmetry sulphate ion and the coordination of water molecules in the lattice.

Electron paramagnetic resonance and optical absorption studies of Cu(II) ions in cadmium malate pentahydrate single crystals

The X-band electron paramagnetic resonance (EPR) studies on a single crystal of Cu(II) ion doped in cadmium malate pentahydrate have been studied over an extended temperature range of 120–390 K. The detailed analysis of EPR spectra reveal that the Cu(II) ion enters the Cd(II) site in the host lattice. From the observed EPR spectrum, the spin-Hamiltonian parameters have been evaluated. The optical absorption spectrum exhibits a broad band and a shoulder which are assigned to the transitions 2 B 1g → 2B 2g and 2 B 1g → 2E g respectively. The ground state wavefunction of Cu(II) at room temperature is evaluated.