Molecular ions are formed by passing:

Explanation

Molecular ions are formed by passing high energy electron beam, X-rays or α-particles: Passing a high-energy electron beam through a sample can lead to the ionization of molecules. The high-energy electrons can knock off electrons from the sample molecules, resulting in the formation of molecular ions. These ions will have a net positive charge due to the loss of electrons. α-particles are helium nuclei consisting of two protons and two neutrons. They are relatively heavy and carry a positive charge. When α-particles interact with molecules, they can cause ionization by removing electrons from the molecules, leading to the formation of molecular ions. X-rays are high-energy electromagnetic waves. When X-rays interact with molecules, they can eject electrons from the molecules, resulting in the formation of positive molecular ions. The energy of X-rays is sufficient to cause ionization by overcoming the binding energy of electrons in the molecules.