Likewise to the previous step, DFT simulations of NEXAFS spectra are performed at O1s and N1s levels for different polarizations of the incident synchrotron beam. In the second part, a different choice to change the nature of the underlying adsorbing surface is made, by switching to Ag(110) and Au(111) with different adducts of molecular oxygen and 1,4-diaminobenzene respectively. The first part of the work focuses on calculation of NEXAFS K-edge spectra both of ethylene and pyridine molecules adsorbed on a silicon surface Si(100), respectively at C1s and N1s/C1s levels for several polarizations of the incident synchrotron beam, by considering different adsorption geometries in both cases. Specific problem addressed in this research concerns the spectroscopy of molecules adsorbed on surfaces. Proper cluster models of these relaxations are taken in consideration to compute NEXAFS spectra at finite level in a molecular orbital approach. This document reports theoretical results of DFT calculations of periodic relaxations and angle-resolved NEXAFS K-edge core spectra for some solid state systems by using a hybrid computational methodology. This green urea employing magnetically induced method could be a contender to the Haber-Bosch process currently used by the current industry which utilizes high temperature and high pressure. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of urea at the peaks of 1690-1600cm⁻¹. The activation energy of α-Fe2O3 NWs for urea production is lower than NPs in the range of 0–1T, whereas it is reversed for higher magnetic induction values. Urea synthesis was done under magnetic field ranges from 0.0–2.5 T. The magnetic properties of the nanowires exhibited different levels of saturation magnetization, for α-Fe2O3 perpendicularly aligned direction (13.18emu/g) and random direction (10.73emu/g). The needle-like shape of hematite nanowires with length ranging from (16 to 25) μm and diameter from 74 to 145nm confirmed by Field emission scanning electron microscopy (FESEM). X-ray Diffractometer (XRD) confirms the peaks of rhombohedral structure of α-Fe2O3 and Raman spectrum analyses confirms the α-Fe2O3 peaks at 410cm⁻¹, 500cm⁻¹ and 616cm⁻¹. α-Fe2O3 nanowires (NWs) synthesized by heating iron wire in a box furnace at (750–800)☌ and as synthesized α-Fe2O3 nanoparticles (NPs) were received to use as a catalyst in the magnetic reaction of urea synthesis.

In addition, it induces magnetic moment value of 36.33 ♛, which confirms the enhanced magnetic behaviour of hematite. The adsorption of gases resulted in a difference in density and net spin of electrons from 68 to 120 and 0 to 21 respectively.

The average adsorption energy is -4.12kcal/mole at different sites.

The adsorption and subsequent dissociative reaction of hydrogen, nitrogen and carbon dioxide gases on the α-Fe2O3 (111) nanowires were investigated using the density functional theory (DFT) method.

Many transition metals form paramagnetic compounds.The catalytic activity of hematite (α-Fe2O3) nanowires under the influence of magnetic field on urea synthesis is considered green.

Although the transition metals are reactive, they are not as reactive as elements belonging to the alkali metals group.

Because of the different oxidation states, it's possible for one element to produce complexes and solutions in a wide range of colors. The complexes split the d orbital into two energy sublevels so that they absorb specific wavelengths of light.

Transition metals form colored complexes, so their compounds and solutions may be colorful.

Atoms of these elements have low ionization energies.

The positive oxidation state means the transition metals typically form ionic or partially ionic compounds. Copper may have a 1+ or 2+ oxidation state. For example, iron commonly carries a 3+ or 2+ oxidation state. Because the subshell is not filled, atoms of the transition metals have positive oxidation states and also display more than one oxidation state.

Their d orbitals become progressively filled as you move from left to right across the periodic table.

By extension, these elements also have high boiling points. The exception is mercury, which is a liquid at room temperature.

The transition metals, as a group, have high melting points.

Most transition metals are grayish or white (like iron or silver), but gold and copper have colors not seen in any other element on the periodic table.

Transition metals look shiny and metallic.

The transition metals are malleable (easily hammered into shape or bent).

They are excellent conductors of heat and electricity.

Transition metals reactivity