Science Constants - Neutron Compton Wavelength h/mnc Symbol: λC,n Value: 1.319590898(10) × 10-15 m Category: - Neutron Particle Constants Description: The Compton Wavelength is the wavelength associated with the mass of any particle, given by λ = h / mc, where h is Planck's Constant, m is the mass of the particle and c is the speed of light. The value quoted above is the Compton Wavelength for a neutron particle.