PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Inorganic chemistry → Solid state chemistry ↓


Magnetic and optical properties of solids


Introduction

The study of magnetic and optical properties in solids is a fascinating aspect of solid state chemistry. These properties determine how materials interact with magnetic fields and light, which affects their practical applications in a variety of technologies.

Magnetic properties of solids

Magnetic properties in materials arise from the motion of electrons. This is mainly due to two forms of electron motion: the orbital motion of electrons around the nucleus, and the rotation of electrons on their own axis. When these motions interact with external magnetic fields, magnetic properties emerge.

Paramagnetism and diamagnetism

Paramagnetism and diamagnetism are fundamental magnetic properties found in solids.

Paramagnetism occurs in materials with unpaired electrons. These unpaired electrons have a net magnetic moment, which causes the material to be attracted by external magnetic fields. In a paramagnetic material, the magnetization increases linearly with the intensity of the applied magnetic field but disappears when the field is removed. Examples of paramagnetic materials include aluminum, platinum, and some transition metal complexes.

Diamagnetism arises from changes in the orbital motion induced in atoms when exposed to an external magnetic field. All electrons in diamagnetic materials are paired, so they have no net magnetic moment in the absence of an external field. When a magnetic field is applied, these materials generate a small, opposing magnetic field, causing slight repulsion. Examples of diamagnetic materials include bismuth, copper, and lead.

Ferromagnetism, antiferromagnetism and ferrimagnetism

Some materials exhibit more complex forms of magnetism:

Ferromagnetism is observed in materials such as iron, cobalt, and nickel. In these materials, the magnetic moments of the atoms are aligned in the same direction even in the absence of an external magnetic field. This alignment arises from an exchange interaction mechanism. The material exhibits a permanent magnetic moment, which can be very strong.

Antiferromagnetism involves materials in which adjacent magnetic moments point in opposite directions. This results in a net magnetic moment of zero. These materials, such as manganese oxide (MnO), exhibit this behavior due to specific electron exchange interactions that prefer opposite alignments.

Ferrimagnetism occurs in materials where the magnetic moments are aligned in opposite directions, which is similar to antiferromagnetism, but the magnitudes of the opposing magnetic moments are unequal. This results in a net magnetization. An example of a ferrimagnetic material is magnetite (Fe 3 O 4).

Visual example: alignment of magnetic moments

        +++++ ----- +++--- North South Mixed Ferromagnetic Antiferrow Ferrimagnetism

Optical properties of solids

Optical properties deal with how solid materials interact with electromagnetic radiation, particularly visible light. When light interacts with a solid material, it can be absorbed, reflected, or transmitted, leading to various optical phenomena.

Absorption, reflection, and transmission

Absorption of light occurs when photons are absorbed by electrons in a solid material, causing the electrons to move to higher energy levels. The specific wavelengths that are absorbed depend on the energy levels available in the material. Strong absorption in the visible spectrum gives materials their color.

Reflection occurs when light waves bounce off the surface of a material, without penetrating the material. Metals usually reflect a large amount of light, which is why they appear shiny.

Transmission is the passage of light through a substance. Transparent substances, such as glass, transmit most of the light, allowing objects to be seen through them.

Refraction and refractive index

Refraction is the bending of light when it passes from one medium to another with a different refractive index. The refractive index is a measure of how much the speed of light is reduced inside a medium.

        n = c / v

Where n is the refractive index, c is the speed of light in vacuum, and v is the speed of light in the material.

Examples of optical phenomena

A classic optical phenomenon is the spectrum of colours that appears when light passes through a prism. This is due to the different refractive indices for different wavelengths, causing the light to spread out into its component colours.

        White Light -------> Prism -------> Spectrum of Colors

Band theory and electronic transitions

To understand magnetic and optical properties it is necessary to have a good understanding of band theory, which describes the energy levels of electrons in solids.

Energy bands: valence and conduction

In solids, closely packed atoms form bands of energy rather than distinct levels. The two most important bands are the valence band, which is filled with valence electrons, and the conduction band, which is higher in energy and normally empty. The difference between these two bands is known as the band gap.

Electronic transitions and band gap

When an electron absorbs energy, which can be in the form of a photon, it can move from the valence band to the conduction band. This transition depends on the band gap energy. Materials with a small band gap absorb in the infrared region, while large band gaps require UV radiation for electronic excitation.

Optical materials: applications

Understanding optical properties is important in designing materials for lenses, lasers, and fiber optics.

Glasses and crystals: Used in lenses, prisms, and other optical components due to their transparency and ability to bend light at desired angles.

Photonic crystals: Structurally alter the light path, important in the development of modern optical devices.

Magnetic materials: applications

Magnetic properties are integral to the development of data storage and electronic devices.

Magnetic storage: Uses ferromagnetic materials in hard drives and magnetic tape.

Magnetic sensors and detectors: Used in a variety of applications, including navigation systems and medical devices such as MRI scanners.

Conclusion

Magnetic and optical properties play a critical role in the functionality of many materials and devices. From the fundamentals of electron interactions with magnetic fields and light to complex applications in modern technology, understanding these properties is critical for advancing materials science and engineering new devices to meet emerging needs.


PHD → 1.3.5


U
username
0%
completed in PHD

← Prev (1.3.4)
Synthesis of solid state materials
Next (1.3.6) →
Superconductivity

Comments 



Magnetic and optical properties of solids

https://www.chemistryelite.com/phd/1.3.5?ceal=en