Equation sheet#
Units#
Constants#
Energy Constant |
Value |
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Energy Unit Converter#
See here for an interactive option.
Unit |
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From classical to Quantum#
Blackbody radiation#
Description |
Equations |
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Energy quantization |
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Average energy of an oscillating dipole |
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Spectral radiation density of blackbody (Planck) |
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Spectral radiation density of blackbody (classical) |
Wave-particle duality#
Description |
Equations |
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Energy of light |
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Photoelectric effect |
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de Broglie relation |
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Kinetic energy |
Atomic spectra of hydrogen and Bohr’s model#
Description |
Equations |
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Hydrogen emission lines |
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Bohr’s radius |
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Energy level in Bohr’s model |
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Emission of hydrogen atom |
Waves#
Description |
Equations |
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Classical nondispersive wave equation |
|
Wave number |
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Frequency |
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Angular frequency |
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Wave speed |
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Euler’s formula |
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Solution of wave equation |
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Interfering traveling waves give standing wave |
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Time-independent Schrodinger equation |
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Time-dependent Schrodinger equation |
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Stationary states are standing waves |
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Normalization |
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Orthogonality |
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Use quantum mechanics when … |
1. |
Quantum-Mechanical Postulates#
The state of a quantum-mechanical particle is completely specified by a wave function
. The probability that the particle will be found at time in a spatial interval of width centered at is given byFor every measurable property of a system, there exists a corresponding operator.
In any single measurement of the observable that corresponds to the operator
, the only values that will ever be measured are the eigenvalues of that operator.If the system is in a state described by the wave function
, and the value of the observatle is measured once on each of many identically prepared systems, the average value (expectation value) of all of the measurements is given by $ $The evolution in time of a quantum-mechanical system is governed by the time-dependent Schrödinger equation $
$
Operators#
Description |
1D |
3D |
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Position |
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Linear momentum |
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Kinetic energy |
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Potential energy |
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Total energy Hamiltonian |
Simple Quantum Systems#
Stationary states#
Description |
Equations |
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Time dependent Schrodinger equation |
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Time independent Schrodinger equation |
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Stationary state wave function |
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Time component of wave function |
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Probability of finding particle in an interval |
|
General solution as linear combination of stationary states |
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Expansion coefficients |
|
Normalization |
Particle in a 1D box#
Description |
Equations |
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Time independent Schrodinger equation |
|
Wave function |
|
Energy eigenvalues |
Particle in a 3D box#
Description |
Equations |
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Time independent Schrodinger equation |
|
Wave function |
|
Energy eigenvalues |
Finite potential well#
Description |
Equations |
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Potential |
|
Reflection probability |
|
Transmission probability |
Commutators and Uncertainty#
Description |
Equations |
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Commutator |
|
Condition of commutation |
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Standard deviation (uncertainty) |
|
Heisenberg uncertainty principle (general) |
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Heisenberg uncertainty principle (position-momentum) |
Spectroscopy#
Vibration: quantum harmonic oscillator#
Description |
Equations |
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Vibrational Schrodinger equation |
|
Wave function |
|
Harmonic approximation |
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Spring constant |
|
Vibrational Schrodinger equation |
|
Wave function |
|
Hermite polynomials |
|
Constant |
|
Energy eigenvalue |
|
Transition dipole moment |
|
Vibrational selection rule |
Rotation: quantum rigid rotor#
Classical rigid rotor#
Description |
Equations |
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Angular momentum |
|
Linear velocity |
|
Moment of inertia |
|
Rotational kinetic energy |
Quantum rigid rotor#
Description |
Equations |
---|---|
Angular momentum operator |
|
z-component of angular momentum operator |
|
Magnitude of angular momentum operator |
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Components of |
|
Components of |
Description |
Equations |
---|---|
Rotational Schrodinger equation |
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Spherical harmonics |
|
Legendre polynomial |
|
Energy eigenvalues |
|
Angular momentum eigenvalues |
|
z-component eigenvalues |
|
Transition dipole moment |
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Rotational selection rule |
Hydrogen atom#
Description |
Equations |
---|---|
Hydrogen atom Schrodinger equation |
|
Effective potential |
|
Wave function |
|
Energy eigenvalues |
|
Rydberg’s constant |
|
Bohr’s radius |
|
Radial probability distribution |
Many Electron and Proton System#
Many electron atom#
Description |
Equations |
---|---|
Helium Schrodinger equation |
|
Orbital approximation |
|
Hartree orbital equations |
Spin#
Description |
Equations |
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Components of |
|
Components of |
|
Eigenvalue of |
|
Eigenvalue of |
Electron spin#
Description |
Equations |
---|---|
Electron spin |
|
Spin up function |
|
Spin down function |
|
Normalization |
|
Orthogonality |
Identical particles#
Description |
Equations |
---|---|
Spin-spin permutation operator |
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Doing nothing |
|
Symmetric eigenvalue |
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Anti-symmetric eigenvalue |
|
Fermions (e.g. electron) |
|
Bosons |
integer spin, symmetric |
Pauli exclusion principle |
|
Slater determinant |
|
Hartree-Fock orbital equations |
|
Molecular orbital by linear combination of atomic orbitals (MO-LCAO) |
|
Variational principle |