Osm Physics by Ashish

Effects of Centrifugal and Coriolis Forces on Earth Let a particle is situated at a point P on the earth whose latitude is \(\lambda\). Assuming point P as origin draw a reference frame whose X' axis is towards east, Y' axis is towards north and Z' axis is vertically upwards as shown in Fig.(1). This reference frame rotates with an angular velocity \(\vec{\omega}\) due to the rotation of the earth. If unit vectors along the axes of reference frame are \(\hat{i}'\), \(\hat{j}'\), \(\hat{k}'\), then \[ \vec{\omega} =\hat{i}'\omega\cos (90)+ \hat{j}'\omega\cos(\lambda) + \hat{k}'\omega\cos(90-\lambda) \qquad ...(1) \] \[ \boxed{ \vec{\omega} = \hat{j}'\omega\cos\lambda + \hat{k}'\omega\sin\lambda } \qquad ...(1) \] If the particle is at rest on the earth, then Coriolis force will be zero and only centrifugal force will appear to be acting on the particle. Let actual acceleration due to gravity at point P i...

Inert Gas Condensation Technique (IGCT)  1. Introduction Inert Gas Condensation (IGC) is a physical vapor deposition (PVD) technique used to synthesize nanoparticles, nanocrystalline thin films, and bulk nanostructured materials . Pioneered by Gleiter et al. in the 1980s, it was the first method used to produce clean nanostructured metals and ceramics with grain sizes in the range of 2–100 nm. The core principle involves evaporating a source material in an inert gas atmosphere , where the evaporated atoms collide with gas atoms, lose kinetic energy, and condense into nanoclusters via homogeneous nucleation. 2. Basic Working Principle A precursor material (metal/alloy/ceramic) is evaporated inside a vacuum chamber backfilled with an inert gas (typically He, Ar, or Xe). The evaporated atoms undergo collisions with inert gas atoms , resulting in thermalization (loss of kinetic energy). Once the vapor becomes supersaturated , homogeneous nucleation occurs → formation...

  Molecular Beam Epitaxy (MBE) Thin Film Deposition Techniques  1. Introduction The rapid development of nanotechnology, semiconductor electronics, optoelectronics, and quantum devices has increased the demand for thin films with atomic-level precision . Conventional thin-film deposition techniques often provide limited control over film thickness, composition, and crystal quality. To overcome these limitations, Molecular Beam Epitaxy (MBE) was developed. Molecular Beam Epitaxy (MBE) is one of the most precise thin-film deposition techniques. It enables the growth of single-crystal (epitaxial) thin films with atomic-layer control under Ultra-High Vacuum (UHV) conditions. The technique is extensively used in the fabrication of semiconductor heterostructures, quantum wells, superlattices, quantum dots, lasers, LEDs, and high-speed electronic devices. MBE is considered the gold standard for research on advanced semiconductor materials because it allows precise control over...

Quantum Particle in a Box - Notes Quantum Particle in a 3D Box Consider a gas molecule in thermal equilibrium at temperature T . At any instant, the velocity components along x, y, and z directions are: v x , v y , v z . Kinetic Energy Components Energy along x-direction: E x = (1/2) m v x 2 = p x 2 / (2m) Where p x is the momentum component along x-direction. Quantum Condition According to quantum mechanics, a moving particle behaves like a wave. For a particle confined in a box of length L x : p x (2L x ) = n x h Where: h = Planck's constant n x = positive integer ħ = h / (2π) p x = ħπ (n x / L x ) Energy in Each Direction E x = (ħ²π² / 2m) (n x / L x )² E y = (ħ²π² / 2m) (n y / L y )² E z = (ħ²π² / 2m) (n z / L z )² Total Energy E i = E x + E y + E z E i = (ħ²π² / 2m) [ (n x ² / L x ²) + (n y ² / L y ²) + (n z ² / L z ²) ] Here, E i represents the energy of the i-th state def...

Unit I    Thermal and adiabatic interactions: Thermal interaction,  Zeroth law of thermodynamics, systems in thermal contact with a heat reservoir (canonical distribution), Energy Fluctuations, Entropy of a system, Helmholtz free energy, Adiabatic interaction and enthalpy, General interaction and first of thermodynamics, Infinitesimal general interaction, Gibb's free energy, Phase transitions, Triple point, First and second-order phase transition, Clausius-Clapeyron equation, Vapour-pressure curve, transformation of disorder into order, Heat engine and efficiency of engine, carnot's Cycle; Thermodynamic scale as an absolute scale, Maxwell relations and their applications.   Unit II  Kinetic Theory: Derivation of Maxwell's law of distribution of velocities and its experimental verification, most probable, average and RMS velocities, Diffusion, Equipartition Theorem, Classical theory of Specific heat capacity, the specific heat of solid (Explanation...

  Thermal evaporation is a common Physical Vapor Deposition (PVD) technique used to create thin films of material on a substrate . The process involves heating a solid source material within a high-vacuum chamber until it vaporizes; these vaporized atoms or molecules then travel in a straight line to a cooler substrate, where they condense to form a thin, uniform coating.  Core Mechanism The process relies on three critical components to ensure high-quality film deposition:  High Vacuum Environment: Typically conducted at pressures below 10^{-5}Torr. This provides a "mean free path"—the average distance a particle travels before colliding with another—that is longer than the distance between the source and the substrate, ensuring atoms arrive unscattered. Heating Source: The material is heated until its vapor pressure becomes significant. Condensation: The vapor reaches the substrate (e.g., a silicon wafer or glass slide) and transitions back into a solid state, buil...

 Syllabus :  Generic Methodologies for Nanotechnology: Introduction and classification, What is nanotechnology? Classification of nanostructures: Nanoscale architecture; The free electron model and energy bands, Crystalline solids, Periodicity of crystal lattices, Electronic conduction ; Effects of the nanometer length scale , Changes to the system total energy, Changes to the system structure , How nanoscale dimensions affect properties. 1. Introduction to Nanotechnology Nanotechnology is the branch of science and engineering that deals with the study, design, synthesis, characterization, and application of materials and devices at the nanometer scale . The word nano is derived from the Greek word nanos , meaning dwarf . In measurement, 1 nanometer (nm) = 10⁻⁹ meters Nanotechnology focuses on materials whose size ranges from 1 nm to 100 nm . At this scale, materials exhibit unique physical, chemical, electrical, mechanical, and optical properties that differ significantly ...

  Solvothermal Synthesis (Hydrothermal Synthesis) 1. Introduction to Solvothermal Synthesis Solvothermal synthesis is a solution-based, liquid-phase method for producing crystalline materials — particularly nanomaterials — by carrying out chemical reactions in a sealed vessel (autoclave) at temperatures above the boiling point of the solvent , typically in the range of 100–300°C , under autogenous pressure (self-generated pressure from solvent vapor). Hydrothermal synthesis is the specific case where the solvent is water . Solvothermal synthesis is the broader term encompassing any solvent (organic or inorganic). Why "Solvo"thermal? Term Solvent Typical Temperature Hydrothermal Water (H₂O) 100–374°C Solvothermal Any solvent (ethanol, DMF, ammonia, etc.) 100–300°C Glycothermal Glycols (ethylene glycol, glycerol) 150–300°C Ammonothermal Liquid ammonia (NH₃) 100–400°C 2. Basic Principle The core principle of solvothermal synthesis is: Increase temperature → Increase solvent...