Value Of Magnetic Moment Research Articles

Line intensities of the 01111–00001 magnetic dipole absorption band of 12C16O2: Laboratory measurements

The spectra of carbon dioxide in the 3.3 µm region were recorded at three pressures using Bruker IFS 125 HR Fourier transform spectrometer and a 30 m base multipass gas cell of V.E. Zuev Institute of Atmospheric Optics SB RAS. Several lines of the 01111–00001 (ν2 + ν3) magnetic dipole band of 12C16O2 were detected and their line intensities were measured. The vibrational transition magnetic dipole moment was fitted to the observed line intensities. The fitted value of the vibrational transition magnetic dipole moment of 0.71(1)µN is substantially smaller than the value of 0.96µN obtained in the result of the analysis of the Martian atmosphere spectra (here µN is the nuclear magneton). Using the known set of the effective Hamiltonian parameters and fitted value of the vibrational transition magnetic dipole moment the list of the line parameters of this band was generated for the HITRAN database. In addition the line intensities of the R-branch of the electric dipole 01111–00001 band of the 16O12C18O isotopologue were measured for the first time.

Structural Changes in Five‐Coordinate Bromido‐bis(o‐iminobenzo‐semiquinonato)iron(III) Complex: Spin‐Crossover or Ligand‐Metal Antiferromagnetic Interactions?

AbstractSpin‐crossover metal complexes represent important building blocks for a future generation of electronic and optical devices. Pentacoordinated o‐iminosemiquinonate iron(III) complexes are able to demonstrate spin transitions between high spin (HS) and intermediate spin (IS) states under the influence of temperature or irradiation. Studied (MeimSQ)2FeBr sample showed a broad magnetic transition in the temperature region from 30 K to 300 K. Remarkably that observed behavior of magnetization can be interpreted with two controversial models. In the first model, the values of the effective magnetic moment at low temperature and high temperature can be assigned to the IS and HS magnetic moment of ferric ion coupled antiferromagnetically to radical anion ligands. In the second model, the metal spin on metal center remains IS in the whole temperature interval, while the mutual orientation of three magnetic moments in the molecule undergo changes due to exchange interactions. In this work we apply density functional theory and X‐ray absorption spectroscopy to unravel the origin of magnetic properties of the complex. Temperature‐induced changes of interatomic distances in the first coordination sphere support the second model. Such comprehensive analysis of the magnetic properties makes it possible to shed light on the nature of spin transitions in complexes of transition metals with open‐shell ligands, which are often complicated by strong exchange interactions.

On the Dirac operator for a test electron in a Reissner–Weyl–Nordström black hole spacetime

The present paper studies the Dirac Hamiltonian of a test electron with a domain of bi-spinor wave functions supported on the static region inside the Cauchy horizon of the subextremal RWN black hole spacetime, respectively inside the event horizon of the extremal RWN black hole spacetime. It is found that this Dirac Hamiltonian is not essentially self-adjoint, yet has infinitely many self-adjoint extensions. Including a sufficiently large anomalous magnetic moment interaction in the Dirac Hamiltonian restores essential self-adjointness; the empirical value of the electron's anomalous magnetic moment is large enough. The spectrum of the subextremal self-adjoint Dirac operator with anomalous magnetic moment is purely absolutely continuous and consists of the whole real line; in particular, there are no eigenvalues. The same is true for the spectrum of any self-adjoint extension of the Dirac operator without anomalous magnetic moment interaction, in the subextremal black hole context. In the extremal black hole sector the point spectrum, if non-empty, consists of a single eigenvalue, which is identified.

Prediction of structural, electronic and magnetic properties of full Heusler alloys Ir2YSi (Y = Sc, Ti, V, Cr, Mn, Fe, Co, and Ni) via first-principles calculation

First principles electronic structural calculation of full Heusler alloys Ir2YSi (Y= Sc to Ni) in the L21 (Cu2MnAl) and Xa (Hg2CuTi) structures have been studied using full-potential linearized augmented plane wave method (FP-LAPW) based on density functional theory (DFT). From the total energy calculations, it has been observed that all these alloys are stable in L21 structure than Xa structure and also it is found that the alloys Ir2YSi (Y =V to Co) are ferromagnetically stable whereas the Ir2YSi (Y = Sc, Ti, and Ni) alloys are non-magnetic in their stable L21 structure. Spin polarized band structure calculations reveal that in Ir2YSi (Y= V to Co) alloys there is spin splitting of energy states around the Fermi level (EF) indicating ferromagnetism and moreover in Ir2YSi (Y = V, Cr, and Mn) alloys majority electrons have metallic behavior while minority electrons have semiconducting nature exhibiting half metallic ferromagnetic (HMF) nature. HMF property in Ir2YSi (Y = V, Cr, and Mn) alloys have been further confirmed from the integer total magnetic moment value of 3.0 µB, 4.0 µB and 5.0 µB per formula unit respectively. Spin polarization mainly arises from the interaction between 3d electrons of V/Cr/Mn atom and 5d electrons of Ir atom. This strong d-d hybridization between the transition atoms like Ir and V/Cr/Mn composing Heusler alloys is essential for the formation of gap at the EF between the valence and conduction bands. Our results show that Ir2YSi (Y= V, Cr, and Mn) will be suitable for ferromagnetic and spintronics applications.

First Principle Calculations of Effect of Hydrostatic Pressure on Ga0.75Cr0.25P

In this paper, the investigation of effect of hydrostatic pressure on the structural, electronic and magnetic properties of Ga0.75Cr0.25P ternary alloy in Zinc Blende (B3) phase at 0 GPa to 26 GPa pressure range has been done using first principle calculations as implemented in Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA) code. The theoretical investigation of electronic and magnetic properties of this compound represents that the compound is half-metallic ferromagnet and show 100% spin polarization at different values of pressure. It is found that band gap increases with increase in pressure as spin polarized band structures experience changes with applied pressure. The calculated results show that lattice constant and volume of compound decrease along-with increase in induced local magnetic moments values on non-magnetic gallium and phosphorus atoms with applied pressure.

DFT Study of Effect of Hydrostatic Pressure on Structural, Electronic and Magnetic Properties of In0.875Cr0.125P

In this paper, the effect of hydrostatic pressure on structural, electronic and magnetic properties of In0.875Cr0.125P Diluted Magnetic Semiconductor (DMS) in Zinc Blende (B3) phase has been studied at 0 GPa to 26 GPa. The calculations have been performed using Density Functional Theory as implemented in the Spanish Initiative for Electronic Simulations with Thousands of Atoms code (SIESTA) using LDA+U (U=3) as exchange-correlation (XC) potential. The study of electronic structures and magnetic properties show that In0.875Cr0.125P is half metallic in nature and this behaviour is maintained at given pressure range. It is found that forbidden energy band gap increases with increase in pressure due to shifting of valence band maximum and conduction band minimum of energy levels. The investigation of structural properties shows that lattice constant and volume of compound decreases along with increase in total energy of compound with applied pressure. The study of induced local magnetic moment values show their continuous increase on non-magnetic indium and phosphorus atoms with increasing pressure.

First-principles study of C cites vacancy defects in water adsorbed Graphene

The electronic and magnetic properties of water adsorbed graphene (wad – G), single carbon (1C) atom vacancy defects in water adsorbed graphene (1Catom-vacancy – wad – G) and double carbon (2C) atoms vacancy defects in water adsorbed graphene (2Catom-vacancy – wad – G) materials are studied by first-principles calculations within the frame work of density functional theory (DFT) using computational tool Quantum ESPRESSO (QE) code. We have calculated the binding energy of wad – G, 1Catom-vacancy – wad – G and 2Catom-vacancy – wad – G materials, and then found that non-defects geometry is more compact than vacancy defects geometries. From band structure calculations, we found that wad – G is zero band gap semiconductor, but 1Catom-vacancy – wad – G and, 2Catom-vacancy – wad – G materials have metallic properties. Hence, zero band gap semiconductor changes to metallic nature due to C sites vacancy defects in its structures. We have investigated the magnetic properties of wad – G and its C sites vacancy defects materials by using Density of States (DOS) and Partial Density of States (PDOS) calculations. We found that wad – G is non- magnetic material. 1C atom vacancy defects in graphene surface of wad – G is induced magnetization by the re-bonding of two dangling bonds and acquiring significant magnetic moment (0.11 µB/ cell) through remaining unsaturated dangling bond. But, 2C atoms vacancy defects in graphene surface of wad – G induced low value of magnetic moment (+0.03 µB/ cell) than 1C atom vacancy defects in structure, which is due to no dangling bonds present in the structure. Therefore, non-magnetic, wad – G changes to magnetic, 1Catom-vacancy – wad – G and, 2Catom-vacancy – wad – G materials due to C sites vacancy defects in wad – G structure. The 2p orbital of carbon atoms has main contribution of magnetic moment in defects structures.

Crystal structure and magnetic properties of R11Co4In9 (R=Tb, Dy, Ho and Er) compounds

Crystal structure and magnetic properties of the R11Co4In9 compounds (R = Tb–Er) have been investigated by means of X-ray diffraction as well as dc magnetic measurements. The compounds crystallize in the orthorhombic Nd11Pd4In9-type crystal structure (Cmmm space group) in which the rare earth atoms occupy five nonequivalent sublattices. Magnetic properties of the investigated compounds are related mainly to the R3+ ions. The values of effective magnetic moments in the paramagnetic state are close to the free R3+ ion values while the moments in the ordered state at T = 2.0 K (R = Tb, Dy) or T = 1.9 K (R = Ho, Er) and H = 90 kOe are lower than the respective R3+ moments. The compounds show complex magnetic properties below 95 K (Tb), 88 K (Dy), 35 K (Ho) and 5.4 K (Er). With increase of temperature the antiferromagnetic ground state changes to the ferro- or ferrimagnetic one. The critical temperatures of magnetic ordering do not fulfill the de Gennes scaling indicating a strong influence of the crystal electric field (CEF) in stabilizing the magnetic order.

Synthesis, characterization, ADMET, in vitro and in vivo studies of mixed ligand metal complexes from a curcumin Schiff base and lawsone

Complexes are currently synthesized from plant origin because of their therapeutic effect against certain diseases with toxicity. Hence, in this work, four new transition metal(II) mixed ligand complexes have been synthesized using a curcumin Schiff base (primary ligand) and lawsone (as co-ligand). The geometry of these complexes was explored by elemental analyses, molar conductance, thermal analysis, magnetic moment values, IR, NMR, Mass, electronic and EPR spectral studies. Electronic absorption titrations, viscosity measurements and molecular docking studies reveal that all the metal complexes interact with the CT DNA by groove binding. Among all the complexes, the copper(II) complex (complex 1) exhibits a higher Kb value (3.5 × 10−4 M) which reveals that it has a strong binding efficiency toward the CT DNA. The complexes also possess strong DNA cleavage efficiency. Cytotoxicity investigations on Artemia salina show that all the complexes possess higher cytotoxic effect than the ligand. Moreover, all the metal complexes have better antimicrobial efficacy than the ligand. Swiss ADME, PASS and pkCSM online softwares are helpful to predict the pharmacokinetic and biological actions of the curcumin Schiff base. Theoretical results obtained from the in silico study are experimentally corroborated by in vivo anti-inflammatory screening study. All the above studies demonstrate that the copper complex possesses biological activity similar to that of the drug like molecules. Research Highlights Synthesis and characterization of four novel transition mixed ligand complexes using plant moieties Promising in vivo anti-inflammatory agents and in vitro DNA metallonucleases Cytotoxicity investigation on Artemia salina Higher cytotoxic effect for the complexes than the ligand Identification of copper(II) complex as lead like molecule among all

Influence of Pr substitution on the physical properties of the Ce1−xPrxCoGe3 system: Combined experimental and first-principles study

We present the results of our investigations of physical properties for the novel Ce$_{1-x}$Pr$_x$CoGe$_3$ system performed with a number of experimental methods: magnetic susceptibility, specific heat, electrical resistivity, magnetoresistance, and thermoelectric power. Moreover, the electronic structure was studied by means of photoelectron spectroscopy measurements and first-principles calculations. All investigated compositions of the Ce$_{1-x}$Pr$_x$CoGe$_3$ series crystallize in the tetragonal BaNiSn$_3$-type structure. The lattice parameters and unit cell volumes decrease with increasing Pr concentration. On the basis of the measurements taken, a preliminary magnetic phase diagram was created. A continuous suppression of the long-range magnetic ordering was observed with increase of Pr concentration. The critical Pr concentration for magnetic moment ordering was determined from linear extrapolation of the ordering temperature $versus$ $x$ to the lowest temperatures ($T = 0$ K) and is equal to about 0.66. Based on the first-principles calculations we show how the substitution of Pr for Ce affects the electronic structure and magnetic properties of the considered alloys. Within a single model we take into account the magnetic ordering, fully-relativistic effects, and Hubbard U repulsion on Ce and Pr. The impact of Hubbard U on the results of calculations is also discussed. We present the valence-band analysis, Mulliken electronic population analysis, and calculated electronic specific heat coefficients. For CeCoGe$_3$ it is found that the $++--$ configuration of magnetic moments on Ce is slightly more stable than the $+-+-$ one, and also that the calculated value of total magnetic moment on Ce (including spin and orbital parts) is in good agreement with the measurements.

Tuning of ferromagnetic behavior of GaN films by N ion implantation: An experimental and first principle-based study

Magnetic properties of N-ion implanted GaN films (150 nm) have been reported. It is found that GaN films grown by the MOCVD technique show strong room temperature ferromagnetic behavior, which can be tuned by implanting N-ions at different fluences (1 × 1015 to 5 × 1016 ions-cm−2). Presence of implanted N at interstitial sites of the GaN host matrix is indicated from the strain observed in GaN by analysis of XRD data. PL spectra show presence of different types of defects in the as deposited film and engineering of defects after N-ion implantation. XPS spectra of Ga 3d-core level and valence band reveal the bonding of implanted N with the host Ga and/or N. The origin of ferromagnetic behavior is ascribed to unpaired electrons created at N sites due to Ga vacancies. First principle-based calculations also confirm ferromagnetism due to Ga vacancies and the reduction of magnetic behavior in Ga deficient GaN with N-ion implantation at interstitial site. The systematic reduction in the saturation magnetic moment value after N-ion implantation is explained on the basis of pairing of the unpaired electrons due to the bond formation of interstitial N with Ga and N present in the host matrix.

Raman and in-field 57Fe Mössbauer study of cation distribution in indium (In) substituted phase pure cobalt ferrite (CoFe2−xInxO4)

Structural, magnetic and 57Fe Mössbauer investigations of indium (In) doped cobalt ferrite are reported. Polycrystalline CoFe2−xInxO4, x = 0, 0.2, 0.4, 0.6, 0.8 samples are prepared by sol–gel method. In contrast to most of the literature, in the present work phase pure samples are obtained, except for x = 0.2. The presence of ferrimagnetic ordering in all the samples is confirmed from in-field 57Fe Mössbauer spectroscopy measurements. The cation distribution is obtained unambiguously from the combined analysis of Raman and in-field 57Fe Mössbauer spectroscopy measurements. The variation of magnetic moment values calculated from the obtained cation distribution are found to match qualitatively with the experimental values, supporting the analysis of in-field 57Fe Mössbauer and Raman spectroscopy measurements.

Electronic and Thermoelectric Properties of Li-Based Half-Heusler Alloys: A DFT Study

Abstract In this paper, we have studied the electronic, elastic and thermoelectric properties of the half-Heusler LiCrZ (Z = C, N, Si, and P) materials in Type II phase, in this structure the atomic occupations are X (1/2,1/2,1/2), Y (0,0,0) and Z(1/4,1/4,1/4). The ferromagnetic state of Type II structure was found to be the most stable phase for all studied alloys. After calculating the elastic constants, we found out that the conditions of mechanical stability were verified only for LiCrSi and LiCrP alloys in Type II phase, at both equilibrium a0 and half metallic ahm lattice constants, which indicates that these two compounds can be synthesized experimentally. We should also mention that the half metallic behavior in Type II structure, for LiCrSi and LiCrP compounds, was obtained by straining the equilibrium lattice constants by 2% and 6%, respectively. At ahm, these two systems were identified to be true half metals due to their complete spin polarization and integer value of total magnetic moment. These last ones have reached 3μB per unit cell when Z = Si, and 4μB when Z = P. Using the mean field approximation (MFA), the Curie temperatures of Type II structure were also determined, where the values are estimated to be 456.2 K and 302.8 K, respectively. Finally, the thermoelectric performance has been explored by the classical Boltzmann theory. At low temperatures, the figure of merit has reached 0.73 and 0.93 for LiCrSi and LiCrP, respectively. The considerable ZT values and all calculated physical properties make these two systems promising candidates for thermoelectric applications.

Understanding the MiniBooNE and the muon and electron g \u2212 2 anomalies with a light Z\u2032 and a second Higgs doublet

Two of the most widely studied extensions of the Standard Model (SM) are a) the addition of a new U(1) symmetry to its existing gauge groups, and b) the expansion of its scalar sector to incorporate a second Higgs doublet. We show that when combined, they allow us to understand the electron-like event excess seen in the MiniBooNE (MB) experiment as well as account for the observed anomalous values of the muon magnetic moment. A light Z′ associated with an additional U(1) coupled to baryons and to the dark sector, with flavor non-universal couplings to leptons, in conjunction with a second Higgs doublet is capable of explaining the MB excess. The Z′ obtains its mass from a dark singlet scalar, which mixes with the two Higgs doublets. Choosing benchmark parameter values, we show that mathrm{U}{(1)}_{B-3{L}_{tau }} , which is anomaly-free, and U(1)B, both provide (phenomenologically) equally good solutions to the excess. We also point out the other (anomaly-free) U(1) choices that may be possible upon fuller exploration of the parameter space. We obtain very good matches to the energy and angular distributions for neutrinos and anti-neutrinos in MB. The extended Higgs sector has two light CP-even scalars, h′ and H , and their masses and couplings are such that in principle, both contribute to help explain the MB excess as well as the present observed values of the muon and electron g − 2. We discuss the constraints on our model as well as future tests. Our work underlines the role that light scalars may play in understanding present-day low-energy anomalies. It also points to the possible existence of portals to the dark sector, i.e., a light gauge boson field (Z′) and a dark neutrino which mixes with the active neutrinos, as well as a dark sector light scalar which mixes with the extended Higgs sector.

New pyrazole‐4‐carbothioamide‐based metal complexes: Synthesis, spectral characterization, computational, antimicrobial, and antitumor investigations

A series of 5‐hydroxy‐4‐(N‐substituted carbothioamide) pyrazole derivatives (HL1–HL5) and their iron(III), nickel(II), and copper(II) complexes have been synthesized. Structural elucidations of the isolated ligands and their complexes are basically accomplished by FT‐IR, 1H NMR, 13C NMR, UV–Vis, ESR, MS, and thermogravimetric analysis (TGA). The analytical data propose the stoichiometries 1:3 (M:L) for Fe(III) and 2:3 for both Ni(II) and Cu(II) complexes. The spectral data substantiate the bidentate coordination mode for all ligands towards metal ions via S and O atoms of CS of the carbothioamide group at pyrazole‐C4 and OH group at C(5) where deprotonation occurs from the enolic tautomer on chelation. Likewise, bidentate pattern of a bridged acetate group is confirmed in the case of Ni(II) and Cu(II) complexes. The magnetic moment values validate high spin octahedral geometry for Fe(III) complexes whereas the diamagnetic feature of Ni(II) complexes is in conformity with the square planar symmetry of low spin state. ESR spectra of all Cu(II) complexes support their existence in distorted square planar geometry with a considerable electron exchange between two copper ion centers of dinuclear type. TGA and DTG analysis of six complexes display their considerable thermal stability. Besides, the in vitro biological screening effects of some selected compounds are tested against various human pathogen microorganisms. Among the ligands, HL5 exhibits the greatest antibacterial activity against two Gram‐positive species (Bacillus subtilis and Staphylococcus aureus) and one Gram‐negative (Proteus vulgaris) in comparison with gentamicin drug. Furthermore, IC50 values of [Cu2(L5)3(OAc)] complex reveal its significant anticancer activity against the three tumor cell lines HCT‐116, MCF‐7, and HepG‐2 compared with imatinib and cisplatin as positive controls. Finally, the optimized structures of all ligands and their molecular electrostatic potential surfaces are established by utilizing density functional theory (DFT).

Electrical and magnetic properties of ZnCr2S4 – nanoparticles

The results of magnetic and electrical measurements of ZnCr2S4 – nanoparticles (NPs) synthesized by mechanical alloying method showed an almost ideal paramagnetic state with the weak ferromagnetic short-range interactions derived from a small positive paramagnetic Curie-Weiss temperature of θ = 0.9 K and the presence of magnetic NPs confirmed by the significantly lower value of the effective magnetic moment (μeff = 2.089 μB/f.u.) compared to the μeff = 5.215 μB/f.u. for bulk spinel as well as n-type semiconducting behavior with an extrinsic region not thermally activated and with an intrinsic region with an activation energy of 0.253 eV. Broadband dielectric spectroscopy measurements showed the relaxation processes only in the intrinsic region of the electrical conductivity, i.e. above 170 K, in which the dipole relaxation becomes faster as temperature rise. These results are interpreted in the framework of the Cole-Cole function and a hopping variable range model including structural defects.

Peculiarities of the phase transformation dynamics in bulk FeRh based alloys from magnetic and structural measurements

We analyze coexistence of antiferromagnetic and ferromagnetic phases in bulk iron-rhodium and its alloys with palladium, Fe50,4Rh49,6, Fe49,7Rh47,4Pd2,9 and Fe48,3Rh46,8Pd4,9, using neutron diffraction, magnetization and scanning Hall probe imaging. Temperature dependencies of the lattice parameters, AFM and FM phase weight fractions, and Fe magnetic moment values were obtained on cooling and heating across the AFM-FM transition. Substantial thermomagnetic hysteresis for the phases’ weight fractions and a relatively narrow one for the unit cell volume has been observed on cooling-heating. A clear dependence of hysteretic behavior on Pd concentration has been traced. Additional direct magnetic measurements of the spatial distribution of the phase transition are acquired using scanning Hall probe microscopy, which reveals the length scale of the phase coexistence and the spatial progression of the transition in the presence of external magnetic field. Also, the magnetic phase diagram has been constructed for a series of Pd-doped FeRh alloys.

Semiconducting and magnetic properties within B(1-x)VxAs alloys at x = 0 and x = 0.25: A DFT + U study

The physical (mechanical (structural and elastic), electronic and magnetic) properties of the zincblende BAs parent compound and its B0.75V0.25As alloy are analyzed by employing the FP-L/APW + lo method as implemented in WIEN2k code, where the XC potential is approached by the GGA approximation. The analysis of the structural properties in B0.75V0.25As system indicates its stability in ferromagnetic state, where its computed equilibrium lattice parameters (the lattice constant (a0), the bulk modulus (B0), and the first-pressure derivative (B’) of the bulk modulus) are given. The elastic moduli (C11, C12, and C44) and anisotropy factor for the cubic system are determined for these compounds in the purpose to confirm their mechanical stability. The electronic structure of B0.75V0.25As shows its complete semiconducting feature. The electronic density of states indicates that the uncompleted 3d-V orbitals broaden on the width of the exchange splitting energies (Δx(d) and Δx(pd)); accordingly, the effective potential of minority-spin electrons are more attracted comparing to the majority-spin electrons. The magnetic properties unveil that the value of total magnetic moment of B0.75V0.25As alloy is found in an integer number. Thus, the hybridization between 3d-V and 4p-As states pushes to reduce the atomic magnetic moment of V element from its free space charge value and to produce local magnetic moments on B and As nonmagnetic sites. Moreover, the s-d exchange constant of conduction band (N0α) and the p-d exchange constant of valence band (N0β) are evaluated in the reason to know contributions during the exchange splitting process.

Synthesis and spectral analysis of some metal complexes with mixed Schiff base ligands 1-[2-(2-hydroxybenzylideneamino)ethyl]pyrrolidine-2,5-dione (HL1) and (2-hydroxybenzalidine)glycine (HL2)

In this paper, new metal ions complexes of [chromium (III), iron (III), cobalt(II), nickel(II), copper(II) and cadmium(II)] were prepared from mixed Schiff base ligands 1-(2-aminoethyl) pyrrolidine-2,5-dione ligand which was prepared form the reaction of the succinic anhydride with ethylenediamine then reacted with salicyaldehyde to form a new Schiff base ligand1-[2-(2-hydroxybenzylideneamino)ethyl]pyrrolidine-2,5-dione (HL1) . The amino acid (glycine) was reacted with salicyaldehyde to form another new Schiff base ligand (2-hydroxybenzaldine)glycine (HL2) . The two types of Schiff bases ligands (HL1) , (HL2) were mixed with some metal ions [(Cr+3, Fe+3, Co+2, Ni+2, Cu+2 and Cd+2)] to obtain a new metal complexes. The Schiff base ligands were characterized by physic-chemical spectroscopic techniques such as: FT-IR Spectra, UV-Vis. Spectra, mass spectroscopy, 1HNMR and microanalysis techniques (C.H.N). Which is indicated the purity of Schiff base ligands. The fragments of the prepared free Schiff base ligand (HL1) were identified by mass spectrometer technique. The metal complexes were characterized by spectroscopic techniques such as: FT-IR Spectra, UV-Vis. Spectra, molar conductivity, magnetic moment and microanalysis techniques (C.H.N) and chloride ion percentage. All the analysis of ligands and their metal complexes were in good agreement with the theoretical values which indicated the purity of Schiff base ligands and their metal complexes. From the above data, the molecular structures for all the metal complexes were proposed to be octahedral. The values of magnetic moments showed that all metal complexes are paramagnetic except cadmium (II) complex which is diamagnetic. The values of molar conductivity also appeared that all metal complexes are non-electrolytic nature except iron (III) complex which is electrolytic.

Reinforcement of Quaternary Ammonium Modified Silica (QAMS) with Magnetite and its Application by Solid Phase Adsorption (SPA) to Adsorb Chromate Ions

Chromium (VI) in the form of chromate anions that have toxic properties needs to be overcome. This study aims to reinforce cationic sorbent quaternary amine-modified silica with magnetite (QAMS-Fe3O4) to adsorb chromate ions. QAMS prepared by reflux methylation ammine modified silica (AMS) obtained from destruction silicate from rice husk ash followed by the addition of 3-APTMS. Characterization QAMS-Fe3O4 by FT-IR showed successfully of methylation process indicated by disappearing absorbance at 1388 cm-1, and emerging absorbance at 2939 cm-1 in QAMS and QAMS-Fe3O4 indicated a transformation of N-H from -NH2 group to [-N+(CH3)3]. XRD analysis denotes 2θ = 30.15°, 35.53°, 43.12°, 57.22°, and 62.90° (JCPDS No. 00-033-0664) fathomed as a characteristic peak of magnetite. SEM-EDX reveals the homogenous topological spherical form with an average particle size 0.006 µm that is dominated by Si element (52.81%) with magnetic moment value = 34.1 emu/g. The stability test shows that this material stable in an acid condition. The adsorption of chromate ions was conducted by the SPA method. Optimal pH obtained by pH range 4-7 with more than 90% adsorbed chromate ions. Variation of increasing series flow rate from 0.05 to 1.5 mL min-1 resulted in decreased adsorbed chromate ions. The use of SPA methods offered simpler and easier handling than the batch method without overriding the adsorption process effectiveness.