Atomic recoil Atomic recoil Atomic recoil is the result of the interaction of an atom with an energetic elementary particle, when the momentum of the interacting particle is transferred to the atom as whole without altering non-translational degrees of freedom of the atom. It is a purely quantum phenomenon. Atomic recoil was discovered by Harriet Brooks, Canada's first female nuclear physicist. If the transferred momentum of atomic recoil is enough to disrupt the crystal lattice of the material, a vacancy defect is formed; otherwise a phonon is generated. Closely related to atomic recoil is electron recoil (see photoexcitation and photoionization), and nuclear
Mass-to-charge ratio a scalar property, meaning that it can be either positive (+) or negative (−). The Coulomb (C) is the SI unit of charge; however, other units can be used, such as expressing charge in terms of the elementary charge (e). The SI unit of the physical quantity "m"/"Q" is kilogram per coulomb. The units and notation above are used when dealing with the physics of mass spectrometry; however, the "m"/"z" notation is used for the independent variable in a mass spectrum. This notation eases data interpretation since it is numerically more related to the unified atomic mass unit. The "m"