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Introduction to Quantum Mechanics
This text focuses on introducing students to the postulates and general principles of quantum mechanics. Application to harmonic oscillator, rigid rotor, one-electron and many-electron atoms, and homo- and hetero-nuclear diatomic molecules are discussed including variational method and time-independent perturbation theory approximations.
- Author
- Delmar Larsen
- Publisher
- University of California, Davis
- Source
- LibreTexts
- License
- CC BY-NC-SA
- Language
- EN
- Category
- Basic Sciences
Contents· 106 sections
- 01: The Dawn of the Quantum Theory
- 1.1: Blackbody Radiation Cannot Be Explained Classically
- 1.2: Quantum Hypothesis used for Blackbody Radiation Law
- 1.3: Photoelectric Effect Explained with Quantum Hypothesis
- 1.4: The Hydrogen Atomic Spectrum
- 1.5: The Rydberg Formula and the Hydrogen Atomic Spectrum
- 1.6: Matter Has Wavelike Properties
- 1.7: de Broglie Waves can be Experimentally Observed
- 1.8: The Bohr Theory of the Hydrogen Atom
- 1.9: The Heisenberg Uncertainty Principle
- 1.E: The Dawn of the Quantum Theory (Exercises)
- 02. The Classical Wave Equation
- 2.1: The One-Dimensional Wave Equation
- 2.2: The Method of Separation of Variables
- 2.3: Oscillatory Solutions to Differential Equations
- 2.4: The General Solution is a Superposition of Normal Modes
- 2.5: A Vibrating Membrane
- 2.E: The Classical Wave Equation (Exercises)
- 03. The Schrodinger Equation and a Particle In a Box
- 3.01: The Schrodinger Equation
- 3.02: Linear Operators in Quantum Mechanics
- 3.03: The Schrodinger Equation is an Eigenvalue Problem
- 3.04: The Quantum Mechanical Free Particle
- 3.05: Wavefunctions Have a Probabilistic Interpretation
- 3.06: The Energy of a Particle in a Box is Quantized
- 3.07: Wavefunctions Must Be Normalized
- 3.08: The Average Momentum of a Particle in a Box is Zero
- 3.09: Particle in a Finite Box (and Tunneling)
- 3.09: The Uncertainty Principle Redux
- 3.10: A Particle in a Two-Dimensional Box
- 3.11: A Particle in a Three-Dimensional Box
- 3.E: The Schrodinger Equation and a Particle in a Box (Exercises)
- 04. Postulates and Principles of Quantum Mechanics
- 4.1: The Wavefunction Specifies the State of a System
- 4.2: Quantum Operators Represent Classical Variables
- 4.3: Observable Quantities Must Be Eigenvalues of Quantum Mechanical Operators
- 4.4: The Time-Dependent Schrodinger Equation
- 4.5: The Eigenfunctions of Operators are Orthogonal
- 4.6: Heisenburg Uncertainy Principle III - Commuting Operators
- 4.E: Postulates and Principles of Quantum Mechanics (Exercises)
- 05. The Harmonic Oscillator and the Rigid Rotator: Two Spectroscopic Models
- 5.1: A Harmonic Oscillator Obeys Hooke's Law
- 5.2: The Equation for a Harmonic-Oscillator Model of a Diatomic Molecule Contains the Reduced Mass of the Molecule
- 5.3: The Harmonic Oscillator is an Approximation
- 5.4: The Harmonic Oscillator Energy Levels
- 5.5: The Harmonic Oscillator and Infrared Spectra
- 5.6: The Harmonic-Oscillator Wavefunctions Involve Hermite Polynomials
- 5.7: Hermite Polynomials are either Even or Odd Functions
- 5.8: The Energy Levels of a Rigid Rotor
- 5.9: The Rigid Rotator is a Model for a Rotating Diatomic Molecule
- 5.E: The Harmonic Oscillator and the Rigid Rotor (Exercises)
- 06: The Hydrogen Atom
- 6.01: The Schrodinger Equation for the Hydrogen Atom Can Be Solved Exactly
- 6.02: The Wavefunctions of a Rigid Rotator Are Called Spherical Harmonics
- 6.03: The Precise Values of the Three Components of Angular Momentum Cannot Be Measured Simultaneously
- 6.04: Hydrogen Atomic Orbitals Depend upon Three Quantum Numbers
- 6.05: s Orbitals Are Spherically Symmetric
- 6.06: Orbital Angular Momentum and the p-orbitals
- 6.07: The Helium Atom Cannot Be Solved Exactly
- 6.E: The Hydrogen Atom (Exercises)
- 07. Approximation Methods
- 7.0: Slater's Rules for Shielding
- 7.1: The Variational Method
- 7.2: Linear Variational Method and the Secular Determinant
- 7.3: Trial Functions Can Be Linear Combinations of Functions with Variational Parameters
- 7.4: Perturbation Theory Expresses the Solutions in Terms of Solved Problems
- 7.E: Approximation Methods (Exercises)
- 08: Multielectron Atoms
- 8.01: Atomic and Molecular Calculations Are Expressed in Atomic Units
- 8.02: perturbation Theory and the Variational Method
- 8.03: Hartree-Fock Equations Are Solved by the Self-Consistent Field Method
- 8.04: An Electron Has An Intrinsic Spin Angular Momentum
- 8.05: Wave Functions Must Be Antisymmetric in the Interchange of Any Two Electrons
- 8.06: Antisymmetric Wave Functions Can Be Represented by Slater Determinants
- 8.07: Hartree-Fock Calculations Give Good Agreement with Experimental Data
- 8.08: A Term Symbol Gives a Detailed Description of an Electron Configuration
- 8.08B: Multi-electron Considerations - A Closer Look at Helium
- 8.09: The Allowed Values of J
- 8.10: Hund's Rules Determine the Term Symbols of the Ground Electronic States
- 8.11: Using Atomic Term Symbols to Describe Atomic Spectra
- 8.E: Multielectron Atoms (Exercises)
- 09: The Chemical Bond: Diatomic Molecules
- 09.1: The Born-Oppenheimer Approximation Simplifies the Schrodinger Equation for Molecules
- 09.2: The H Prototypical Species
- 09.2B: Solving the H System Exactly
- 09.3: The Overlap Integral
- 09.3B: Evaluating the Overlap Integral
- 09.4: Chemical Bond Stability
- 09.5: Bonding and Antibonding Orbitals
- 09.6: A Simple Molecular-Orbital Treatment of H2 Places Both Electrons in a Bonding Orbital
- 09.7: Molecular Orbitals Can Be Ordered According to Their Energies
- 09.8: Molecular-Orbital Theory Predicts that a Stable Diatomic Helium Molecule Does Not Exist
- 09.9: Electrons Are Placed into Molecular Orbitals in Accord with the Pauli Exclusion Principle
- 9.10: Molecular Orbital Theory Predicts that Molecular Oxygen is Paramagnetic
- 9.E: The Chemical Bond: Diatomic Molecules (Exercises)
- MathChapters
- A: Complex Numbers
- B: Probability and Statistics
- C: Vectors
- D: Spherical Coordinates
- E: Determinants
- F: Matrices
- G: Numerical Methods
- H: Partial Differentiation
- I: Series and Limits
- J: The Binomial Distribution and Stirling's Appromixation