de broglie postulation: 1927, Verified by Davisson and germer. They showed that mono-energetic electrons scattered from crystalline nickel foil gave a diffraction pattern analogous to that showed by X-rays Similar experiments were carried out independently by G. P. Thomson, and later Stern showed that beams of heavier particles (H, He, etc.) showed diffraction patterns when reflected from the surfaces of crystals de broglie's expression for the wavelength of these matter waves is of high accuracy.de Broglie postulation:1927,Verified by Davisson and Germer. They showed that mono-energetic electrons scattered from crystalline nickel foil gave a diffraction pattern analogous to that showed by X-Rays. Similar experiments were carried out independently by G. P. Thomson, and later Stern showed that beams of heavier particles (H, He, etc.) showed diffraction patterns when reflected from the surfaces of crystals. de Broglie’s expression for the wavelength of these matter waves is of high accuracy