ThermodynamicsCore Level

Diffusion Calculator

Calculate temperature-dependent diffusion coefficients and model depth concentration profiles using error functions.

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m²/s

Calculated Coefficient

Arrhenius kinetic rate D = D0 * exp(-Q/RT)

Enter valid inputs to compute D.

Formula: Arrhenius Rate Equation

D = D0 · exp(-Q / (R · T))
Where:
D=Diffusion coefficient (m²/s)
D0=Pre-exponential factor (m²/s)
Q=Activation energy (J/mol, kJ/mol, eV/atom)
R=Gas Constant (8.314 J/mol·K) / k_B (8.617e-5 eV/K)
T=Absolute temperature (K)

Scientific Assumptions & Methodology

  • Fick's Second Law for one-dimensional semi-infinite solid holds.
  • Surface concentration Cs is assumed to be constant throughout diffusion.
  • Diffusion coefficient D is independent of composition/concentration.

Limitations & Educational Warnings

  • Does not solve finite-source (Gaussian) boundary conditions.
  • Assumes isotropic structure, excluding grain boundary or surface diffusion enhancements.