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Work Function Calculator

Work out work function instantly with clear inputs, formula shown and shareable results.

About Work Function Calculator

The work function is the minimum energy needed to free an electron from a metal surface, and it corresponds to a threshold frequency phi/h below which no photoemission occurs. A 540 nm threshold implies 2.30 eV, matching potassium. Caesium's low 2.1 eV is why it is used in photocathodes sensitive to visible light.

Formulas

Work function from threshold

phi = h c / lambda(threshold)

Threshold frequency

f0 = phi / h

Worked example

With the default values below, Work Function Calculator returns Work Function of 2.2960. Change any input above and every figure here is recalculated in your browser.

Inputs used

Threshold wavelengthminimum 0 nm
540 nm
Reference metalone of Use the wavelength entered, Caesium (2.1 eV), Potassium (2.3 eV), Zinc (4.3 eV), Platinum (5.6 eV)
Use the wavelength entered

Results

Work Function
2.2960 eV
Threshold Frequency
5.5517 × 10¹⁴ Hz
Work Function In Joules
3.6786 × 10⁻¹⁹
Threshold Wavelength
540.00 nm

Step by step

  1. 1Values used
  2. 2Work function from threshold
  3. 3Threshold frequency
  4. 4Work Function= 2.2960 eV
  5. 5Threshold Frequency= 555,171,000,000,000.0000 Hz
  6. 6Work Function In Joules= 0.0000
  7. 7Threshold Wavelength= 540.00 nm

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why do different metals have different work functions?

Because it depends on how tightly the lattice binds its conduction electrons. Alkali metals hold them loosely; platinum and gold hold them tightly.

Does surface condition matter?

Considerably. Oxide layers and adsorbed gases can shift the work function by an electronvolt, which is why photocathodes are made in vacuum.

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