Moon-Won Kim

Synthesis and properties of nickel(II) and copper(II) complexes of a di-N-acetamide tetraaza macrocycle

Abstract The syntheses of the hexadentate ligand 2,13-bis(acetamido)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane (L2) and its complexes with Ni(II) and Cu(II) are described. Crystal structures of H2L2·2HClO4 (1), [Ni(L2)](ClO4)2 (2) and [Cu(L2)](ClO4)2 (3) are reported. The two pendant acetamide groups of the macrocyclic ligand 1 are trans to each other and the absolute configuration is a trans-IV in the solid state. The crystal structures of 2 and 3 revealed an axially elongated octahedral geometry with four nitrogen atoms of the macrocycle and two oxygen atoms of the pendant acetamide groups at the axial positions. The nickel(II) and copper(II) ions are located at an inversion center. The electronic spectra and electrochemical behaviors of the complexes are significantly affected by the presence of the pendant arms.

SYSTEMATIC DIRAC ANALYSES OF PROTON INELASTIC SCATTERINGS FROM AXIALLY SYMMETRIC DEFORMED NUCLEI

Relativistic Dirac coupled channel analyses using optical potential model are performed for the 800 MeV proton inelastic scatterings from 26Mg and the results are compared with those from several other axially symmetric deformed nuclei for the systematic Dirac analyses. Employing scalar-vector model, scalar and time-like vector optical potentials in Lorentz covariant form are calculated phenomenologically by solving Dirac coupled channel equations using sequential iteration method. Dirac equations are reduced to second-order differential equations to obtain Schrodinger equivalent effective central and spin-orbit optical potentials and it is found that the heavier deformed nucleus has the larger effective central potential strength. Using the first-order rotational collective model to describe the low-lying excited states of ground state rotational band in the deformed nuclei, deformation parameters for the excited states are calculated and it is observed that the lighter deformed nucleus has the larger deformation parameter for the lowest lying excited 2+ state at the 800 MeV proton inelastic scattering, indicating the stronger coupling to the ground state compared to that of heavier nucleus.

Dirac phenomenological analyses of unpolarized proton inelastic scattering from 22Ne

Unpolarized 800-MeV proton inelastic scatterings from an s-d shell nucleus 22Ne are analyzed by using phenomenological optical potentials in the Dirac coupled channel formalism. The first-order rotational collective model is used to obtain the transition optical potentials for the low-lying excited collective states that belong to the ground-state rotational band of the nucleus. The optical potential parameters of a Woods-Saxon shape and the deformation parameters of the excited states are varied phenomenologically by using the sequential iteration method to reproduce the experimental differential cross-section data. The effective central and spin-orbit optical potentials are obtained by reducing the Dirac equations to a Schrödinger-like second-order differential equations, and the surface-peaked phenomena are observed at the real effective central potentials when the scattering from 22Ne is considered. The obtained deformation parameters of the excited states are compared with those of the nonrelativistic calculations and with those for another s-d shell nucleus 20Ne. The deformation parameters for the 2+ and the 4+ states of the ground-state rotational band for the nucleus 22Ne are found to be smaller than those of 20Ne, indicating that the couplings of those states to the ground state are weaker for the 22Ne than for the 20Ne nucleus. The multistep channel coupling effect is confirmed to be important for the 4+ state excitation of the ground-state rotational band for proton inelastic scattering from the s-d shell nucleus 22Ne.

Growth Properties of Sputtered ZnO Thin Films Affected by Oxygen Partial Pressure Ratio

ZnO thin films were grown on a glass by RF sputtering system with RF power 100W and oxygen partial pressure of . Elliptic constants were measured by using a phase modulated spectroscopic ellipsometer and analyzed with the Tauc-Lorentz dispersion formula and best fit method in the range of 1.5 to 3.8eV. Also, scanning electron microscope(SEM) was used for the analysis of surface crystallization condition. From elliptic constants spectra, optical constants, thickness and roughness of ZnO films were evaluated. Total thickness of ZnO films obtained by ellipsometry showed good agreement with SEM data. It was found that the grain size of the films were getting smaller with increasing oxygen partial pressure. Band-gap of ZnO films increase with the oxygen partial pressure. These findings clearly indicate that optical properties of ZnO films are strongly dependent on the oxygen partial pressure. It could be explained that increasing the oxygen partial pressure induced high crystalline imperfection in the ZnO films.

X-ray crystal structure of a macrocyclic tetraamine nitrito nickel(II) complex

The compound [Ni(L)(η2-NO2)]ClO4 (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized and structurally characterized. It crystallizes in the monoclinic system, space group P21/c with a = 26.899(5), b = 8.476(2), c = 23.633(5) Å, β = 115.12(13)°, V = 4878.6(17) Å3, and Z = 4. Each nickel(II) ion has a six-coordinated bicapped square-pyramidal geometry with four secondary amines of the macrocycle and two oxygen atoms of the bidentate nitrito group. Electronic spectra and effective magnetic moment of the complex also exhibit a high-spin six-coordinated geometry.

Dirac coupled-channel analyses of the high-lying excited states at 22Ne(p,p′)22Ne

Dirac phenomenological coupled-channel analyses are performed by using an optical potential model for the high-lying excited vibrational states at 800-MeV unpolarized proton inelastic scatterings from 22Ne nucleus. Lorentz-covariant scalar and time-like vector potentials are used as direct optical potentials, and the first-order vibrational collective model is used for the transition optical potentials to describe the high-lying excited vibrational collective states. The complicated Dirac coupled-channel equations are solved phenomenologically by using a sequential iteration method by varying the optical potential and the deformation parameters. Relativistic Dirac coupled-channel calculations are able to describe the high-lying excited states of the vibrational bands in 22Ne clearly better than the nonrelativistic coupled-channel calculations. The channel-coupling effects of the multistep process for the excited states of the vibrational bands are investigated. The deformation parameters obtained from the Dirac phenomenological calculations for the high-lying vibrational excited states in 22Ne are found to agree well with those obtained from the nonrelativistic calculations using the same Woods-Saxon potential shape.