Ionization Process

 Ionization Process:

Ionization process is the process of formation of free electrons and positive or negative ions.

There are different methods of formation of charges in a gas for ionization process,

• Ionization process by collision
• Photo ionization
• Liberation of Electrons because of the impact of Positive Ion.
• Discharge of Electrons because of Photon energy
• Release of Electrons because of excited particles

If we consider a normal gas molecule or atom, it is normally neutral electrically. Electrically neutral atom has equal number of electrons and protons. Hence it has equal +ve and -ve charges, i.e. total charges of the atoms are in equilibrium.

Hence, due to the same amount of +ve charge and -ve charge, the atom is electrically neutral. If due to any reason electron from neutral atom get liberate, then we observe that there is an imbalance in a number of +ve and -ve charge. The neutral atom becomes +ve ion and also one free electron get form.Because the net +ve charge of an atom is more than -ve charge electrons.

If due to any reason electron gets attach to the neutral atom, then positive ion will be form. Here the number of -ve (electrons) charge becomes more than the number of +ve (protons) charge. The electron attachment and detachment process will be present due to any one of the above reasons.

How Ionization Process occurs?

Here we study how exactly ionization process will occur because of the collision. Consider the figure shown below, here two plane electrodes are considered which are separated by a distance‘d’, and gas is used as the dielectric medium between the electrodes.

Fig:- Ionization Process

The high voltage is present between the electrode set. The electrode connected to -ve terminal of the supply. It is termed as cathode and another connected to the +ve terminal is termed as anode. Due to -ve terminal some of the electrons from the cathode surface get liberate. It is due to repulsive force from -ve terminal.  These electrons gets attract towards anode due to an attractive force.

If the electron is in the outermost orbit of an atom, it is loosely attach with a nucleus. That is an electron has the less force of attraction from the nucleus. Then these electrons can easily detach from an atom by any of the collision processes.

The amount of energy required to detach this outer electron completely and shift the electron. It is to such a distance so that the force of attraction from the nucleus is inactive. It is the first ionization potential. While movement these electrons collides on neutral molecule and produces another free electron and +ve ion.

Know More about Ionization Process:

Again, we observe there is a force of repulsion between previous electron and newly generated electron. Hence these electrons again go on collides with other neutral molecules and produces electrons and +ve ion. This process will be continuous which results in ionized path between electrodes. Ones the gas forms the ions, charges starts moving from one electrode to other electrode. It is  through gas and we say that breakdown in gas occurs.

In this process, when we provide a high voltageacross the electrodes, the electron will acquire sufficient energy. It helps to move electrons from the stable state to the conducting state.

When electrons start moving it gains energy, but when electrons strikes with the neutral atom, the electron loses some energy. Due to attractive forces from an anode and repulsive forces from the cathode electron continues to move.

Hence the ionization process is continuous and forms, conducting path between electrodes.