What is the relationship between energy, frequency, and wavelength?

Use E = h·f and f = c/λ; combining: E = h·c/λ in vacuum.

What is the wavenumber (cm⁻¹) and why is it used in spectroscopy?

It is the spatial frequency ṽ = 1/λ(cm); it is used because it is proportional to energy and linearizes spectral bands.

What is the difference between ν and ṽ?

ν is frequency in Hz, while ṽ is wavenumber in cm⁻¹ (inverse wavelength).

What does the angular frequency ω represent?

It is ω = 2π·f and is used in dynamics and spectroscopy to express frequency in rad/s.

How does the medium (index n) affect the conversion?

Energy and frequency do not change, but the wavelength is reduced: λ_medium = λ_vacuum / n.

How do I use batch mode?

Paste a list of values, choose the input unit, and click “Convert list”; you can export CSV and sort by λ or E.

How is Raman shift calculated?

The laser is converted to wavenumber, the shift is subtracted or added (Stokes/Anti-Stokes), and then converted back to λ.

What are the main limitations?

Propagation in vacuum or constant index n is assumed; dispersion and line widths are not included.

Energy ↔ frequency ↔ wavelength ↔ wavenumber converter

Convert between eV↔J, THz, nm, cm⁻¹ and rad/s with batch mode, spectroscopy (Raman), and CSV/printable export.