Bragg’s Law of Diffraction

Introduction to Bragg’s Law

Bragg’s Law is a fundamental concept in the study of X-ray diffraction, which is used to determine the crystal structure of materials. The law is named after Sir William Lawrence Bragg, a British physicist who, along with his father William Henry Bragg, formulated the law in 1913. Bragg’s Law describes the relationship between the diffraction angle and the spacing of atoms in a crystal lattice.

Understanding Diffraction and X-rays

Diffraction is the bending of waves around obstacles or through openings, and is a characteristic of all wave phenomena, including light, sound, and water waves. X-rays, which are a form of electromagnetic radiation, can diffract when they encounter a crystal lattice. This phenomenon occurs because the atoms in the crystal lattice act as obstacles and cause the X-rays to bend and interfere with each other, resulting in a distinct pattern of diffraction.

Derivation and Application of Bragg’s Law

Bragg’s Law states that when X-rays are incident upon a crystal lattice at a particular angle, the X-rays will be diffracted at an angle that is twice the incident angle, provided that the distance between the planes of atoms in the crystal lattice is equal to the wavelength of the X-rays. This relationship is expressed mathematically as nλ = 2d sin θ, where n is an integer, λ is the wavelength of the X-rays, d is the distance between the planes of atoms in the crystal lattice, and θ is the angle of incidence. Bragg’s Law is used to determine the structure of various crystalline materials, including minerals, proteins, and metals.

Example of Bragg’s Law in Real-life Situations

Bragg’s Law has many practical applications in material science and engineering. For example, it is used to determine the structure of metals, which is important for understanding their mechanical properties and improving their performance in various applications. It is also used in the study of minerals to determine their composition and geological history. In addition, Bragg’s Law is used in the field of protein crystallography, which involves the study of the three-dimensional structures of proteins. This information is valuable for understanding the function of proteins in biological processes, as well as for developing new drugs and therapies.