Proper mass in the context of Relativistic mass

The Compton wavelength is a quantum mechanical property of a particle, defined as the wavelength of a photon whose energy is the same as the rest energy of that particle (see Mass–energy equivalence). It was introduced by Arthur Compton in 1923 in his explanation of the scattering of photons by electrons (a process known as Compton scattering).

The standard Compton wavelength λ of a particle of mass m is given by$${\displaystyle \lambda ={\frac {h}{mc}},}$$where h is the Planck constant and c is the speed of light.The corresponding frequency f is given by$${\displaystyle f={\frac {mc^{2}}{h}},}$$ and the angular frequency ω is given by$${\displaystyle \omega ={\frac {mc^{2}}{\hbar }}.}$$